Smay Pressure Differential Systems Guidebook v514-En

Pressure differential systems

GUIDEBOOK

Awards

THE AUTHORS:

Jarosaw Wiche, Robert Zapaa

COVER AND LAYOUT DESIGN, DTP:

Karol Filas

PUBLISHER:

SMAY Sp. z o.o.

ul. Ciepownicza 29, 31-587 Krakw

www.smay.pl

PPawe Holewa, Grzegorz Kubicki, Grzegorz Sypek,

Table of contents

Pressure Differential Systems in High-rise Buildings GUIDEBOOK

Pressure Differential Systems (PDS) by SMAY introduced innovations

1. Issues connected with design and operation of the Pressure Differential Systems

2. Legal grounds of Pressure Differential Systems design

3. Fire ventilation in multi-storey buildings

3.1. Classification of multi-storey buildings

3.2. Protected spaces in the buildings

3.3. High-rise building as an object of hydraulic connections

3.4. Fire ventilation systems for multistoried buildings

4. Pressure differential solutions offered by SMAY company

4.1. Idea of operation of forced airflow system SAFETY WAY

4.2. SAFET WAY system application in industrial buildings (PM)

4.3. Pressurization of fire-fighting lobbies

5. Air exhaust/release systems

6. Current procedures of testing pressure differential kits

6.1. Functionality and reliability

6.2. Electronic components tests

7. CFD simulations

8. Acceptance testing of pressure differential systems

9. More still to come

10. Data sheets of iSWAY series devices

Belimo Smay Control Device (URBS)

Operating Conditions Monitoring Device (MSPU)

Compact pressurization units tested in laboratory and real scale buildings:

iSWAY tested in real scale building during research and implementation project

iSWAY-FC with electronically controlled by-pass

iSWAY-FCD with multiple pressure control system

iSWAY-FCR with reversible axial flow fans intended for high-rise building

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Pawe Holewa, Grzegorz Kubicki, Grzegorz Sypek,

Modern construction industry includes among other installations and systems providing safety to the users.

Wide range of fire protection solutions has to undergo strict requirements in terms of effectiveness

and reliability. SMAY company, actively participating in the development of this segment, after a dozen

or so months of experiments co-financed by the European Union, has developed an innovative on the european scale active controlled pressure differential system SAFETY WAY . The experimental stage of the research

and implementation project was carried out in cooperation with the scientists of the Warsaw and Krakow

Technical Universities and experienced fire protection experts. Prime aim of the whole project was to develop

and implement new solution that would increase safety level of evacuation in case of fire.

Proper operation and effectiveness of pressure differential system becomes crucial in case of high-rise

buildings where rescue and evacuation action from the outside is hindered of even impossible.

The overall idea of pressure differential systems for smoke and heat control is to generate and maintain fixed

value of pressure difference between escape routes and fire floor (pressure criterion) or directed airflow through

the open door during evacuation (airflow criterion) in order to keep escape routes free of smoke regardless

of actual ambient conditions (e.g. ambient temperature, wind speed and direction). Similar solutions concern

the schemes for lowering pressure but at the moment overpressure systems are the vast majority of applied

pressure differential systems. Generally pressure differential systems are applied to the staircases, elevator

shafts and fire-fighting lobbies but it is also possible to control pressure gradient within horizontal escape

routes. Except of selection the best available technical solution it is also required to fulfill number of additional

requirements which are often ignored by architects and designers leading directly to faulty operation of pressure

differential system. At the design stage of the project it is absolutely necessary to determine exact ductworks

routes as well as air inlets or outlets locations moreover it is obligatory to ensure air release paths at the fire floor.

The conclude properly designed pressure differential system shall fit building construction taking into account

other HVAC installations which may influence its operation.

The past year has also brought lots of changes resulting from European Committee for Standardization (CEN)

working progress which aim is to prepare novelized versions of EN 12101-6 Smoke and heat control systems.

Specification for pressure differential systems. Kits and 12101-13 Pressure differential systems (PDS) design

and calculation methods, acceptance testing, maintenance and routine testing of installation european

Standards. Listed documents shall concern all the issues connected with pressure differential systems design

with special focus on problems underestimated so far such as stack effect, airflow resistance and wind forces

influence. SMAY company basing on the experiences resulting from a variety of pressure differential systems

designed actively supports this initiatives. Out of concern for safety level in case of fire SMAY company as a first

european manufacturer has thoroughly tested offered solutions according to the latest procedures in Institute

of Industrial Aerodynamics GmbH at the Aachen University of Applied Sciences (I.F.I.) and Building Research

Institute (ITB) in Warsaw.

Performed tests have confirmed all declared functional and reliability parameters which is significant advantage

as regards pressure differential systems. It has to be noted that tests results together with positive opinions

of German fire protection experts are the best recommendation of the solutions offered by SMAY company. Within

next few months we may expect introduction of standardized and more strict acceptance tests procedure which

I wish to myself and You!



SMAY company has developed two groups of solutions for protecting both vertical and horizontal escape routes

against smoke and heat in case of fire:

iSWAY series compact pressurization units, which owing to its compact design can be installed in almost

any place in the building. Depending on the chosen design standard it is intended for the buildings not higher

than:

30 m (according to the EN 12101-6 Standard);

55 m (according to the ITB Instruction 378/2002);

65 m (according to the NFPA 92A Standard).

The SWAY /iSWAY solutions are unique on the Polish scale as it fulfills three requirements that are

indispensable to carry out a safe rescue action in a fire-seized building:

SAFETY WAY (SWAY ) forced airflow system intended for buildings where from the point of view

of pressure stabilization inside the staircase stack effect plays an impact role, which is triggered by the

temperature difference between internal air and the ambient. This system may be applied to the wide range

of buildings including industrial buildings with increased heat gains. Depending on the chosen design

standard it is intended for the buildings higher than:

30 m (98 ft.) (according to the EN 12101-6 European Standard);

55 m (180 ft.) (according to French National Regulations, quoted in the ITB Instruction 378/2002);

65 m (213 ft.) (according to NFPA 92A Standard).

achieving and maintaining a stable overpressure in reference to the fire floor in the main part of the staircase

and the fire-fighting lobbies;

maintaining the minimum velocity of directed airflow through the open door between the staircase or fire-

fighting lobby and the corridor (or exit doors at the access level);

controlling overpressure value in the protected spaces so that maximal force required to open evacuation

door has not exceeded 100 N (i.e. 65 Pa of pressure difference across the door).

The most significant advantage of SAFETY WAY active controlled system is that all given requirements are

literally met regardless of the building height and location.

Since November 2008 until October 2010 SAFETY WAY system proper operation has been continuously

controlled and updated. On the one hand projected CFD simulations were carried out at SMAY Research and CFD

Simulations Department. At the same time there were introduced unique on the national scale testing ground

real scale experiments in the high-rise building staircase (23 floors, 90 m high). Developed numerical models

have been verified and validated against real scale measurement data and used to extend the range of analysis

later on.


All the tests were performed with a use of the latest measurement techniques of all up-to-date standards and

that are based on the highest class measurement equipment application. These tests have not only allowed

to develop overall structure of the installation but also what is even more important to work out the measurement

and control system self-adopting to the ambient parameters and evacuation scenarios dynamic changes.

The issue of highest priority was to ensure the highest degree of effectiveness and reliability required pursuant

to the following documents:

ITB Instruction 378/2002. Designing Fire Ventilation Installation for Escape Routes in High Rise Buildings;

NFPA 92A - Standard for Smoke-Control System Utilizing Barriers and Pressure Differences;

EN 12101-6 Standard Smoke and Heat Control Systems. Part 6: Specification for pressure differential

systems Kits.

A special impact was put on fulfilling all the requirements appointed for the pressure differential systems by EN 12010-6 European Standard. The SAFETY WAY system, as the only one in Europe, literally complies with all the

requirements of this Standard as regards of high-rise buildings and polish winter ambient conditions.

The achieved results have enabled to design and implement an innovative pressure differential system supported

by tests carried out in realistic conditions by a panel of experts which effectiveness is confirmed by a number of

acceptance tests in real buildings. The SMAY company as the only one in Poland provides full support at each

stage of the project including: design, CFD simulations assembly as well as on-site start-up and calibration

procedures.

We are warmly encouraging You to learn more about us and our offer in this document. It not only contains the issues associated with the iSWAY /SWAY systems, but also vital information concerning fire ventilation and air

extraction systems, as well as the regulations that need to be met to implement, assemble and use fire

ventilation systems.

The SMAY company, as one of the most modern production companies in the ventilating industry in Poland has its

own design office, testing laboratory, as well as the Research and Development Department. Among its

employees are four PhD's. Last but not least, it has signed contracts for cooperation with the Technical

Universities in Warsaw, Krakow, Gliwice and Wroclaw. Finally, as far as pressure differential is concerned, it has a

representative in European Committee for Standardization (CEN) and American Society of Heating, Refrigeration

and Air Conditioning Engineers Association (ASHRAE).

Marek Maj, SMAY

7version 5.1.4 w w w . s m a y . p l

Issues connected with design and operation of the Pressure Differential Systems

Modern building constructions shall comply with strict requirements regarding safety level in case of fire.

Key issue is to ensure safe evacuation of all people from the building on the basis of evacuation scenario. Since

the most significant threat during evacuation is the risk of toxic fumes inhalation and sustaining burns key issue

is to control temperature and keep all escape routes free of smoke. It is possible assuming that fire ventilation

installations are properly designed and balanced.

The most common installations applied in multi-storey high-rise buildings are pressure differential systems.

Major aims of this solutions regardless of the technical details are to depending on the actual criterion:

generate and control fixed value of pressure difference between selected spaces in order to control smoke

movement inside the building e.g. staircase in reference to the fire floor;

generate directed and controlled airflow through open evacuation door between protected space

and the corridor or open-space.

Overpressure in protected spaces is generated by supplying airflow rate corresponding to the total air leakage

rate of given space. Depending on the protected space type and cubature air can be supplied in different manner:

multiple injection air is supplied to the staircase through the ductwork and multiple inlets located along

the staircase. According EN 12101-6 air inlets shall be located at least every third floor;

concentrated air supply usually with single air inlet located at the bottom or at the top of the staircase.

NOTE: Location and number of air inlet points don't influence significantly static pressure distribution during

pressure criterion within the range of air velocities typical for pressure differential systems.

In order to provide proper operation of pressure differential system it is indispensible to control pressure

difference precisely which is necessary to maintain nominal pressure gradient. According to EN 12101-6

European Standard nominal value of pressure difference depends on the type of the escape route and ranges

between 5 and 50 Pa.

Naturally design process of pressure differential systems becomes more complex as regards of high-rise

buildings. Following phenomena can significantly influence proper pressure differential system operation:

stack effect triggered by proportional to the temperature air density difference between internal air and the

ambient. This phenomenon results in vertical upward or downward movement of air inside the staircase

or elevator shafts. Due to the stack effect stabilizing pressure distribution in pressurized space may

be significantly hindered and application of active controlled pressure differential systems may be necessary

especially as regards of high-rise buildings.

airflow resistance both pressurized staircase and elevator shafts may be considered as a large size ducts.

Regardless of actual ambient parameters during pressurization pressure gradient occurs proportional to the

air supply rate, staircase geometry and building total height. According to the experimental data standard

pressure loss ranges within 2 5 Pa per floor.

wind forces - pressure distribution at the building facade resulting from wind pressure and suction.

NOTE: Properly designed pressure differential system shall be capable to overcome negative influence

of phenomena listed above.

1

8 version 5.1.4w w w . s a f e t y w a y . p l

Issues connected with design and operation of the Pressure Differential Systems 1Due to the problems listed above high-rise buildings pressurization design becomes more complex an often

requires additional analysis which may be performed with a use of analytical calculations, zone-models or CFD

simulations that confirms effectiveness of selected solution.

Mentioned problems and market analysis performed by SMAY company were main reasons for developing innovative active controlled pressure differential system SAFETY WAY which is intended for high-rise and

industrial buildings application. Overall idea of system operation as well as its structure is simple and based

on generation of fully controlled and directed airflow inside pressurized space. Intensity of an airflow

is proportional to the actual value of pressure gradient resulting from stack effect. Key components of the system

are reversible axial flow fans controlled with frequency inverters and a set of pressure controllers equipped with

Belimo fast-acting actuators. System operation is fully automatic additional advantage is that in many cases

system can be assembled as a ductless solution.

Basing on CFD simulations results SMAY company HVAC engineers can select fans as well as suggest locations

of air inlet and outlet points taking into consideration building characteristics and additional requirements.

After initial coarse control carried out with frequency inverter a fine control of set pressure difference is carried

out by means of multiblade dampers equipped with fast actuators operating as pressure controllers. The most

important component of the automation system is URBS (Belimo Smay Control Device) controlling all other devices. URBS is described in details in next chapters. Innovation of SAFET WAY system is also with application

of electronic devices of top quality. That enabled development of reliable active controlled pressure differential

system following-up ambient parameters and evacuation scenarios changes. Additional default component of fully functional SAFETY WAY system is Control Module (MS) which sets airflow direction inside the staircase

basing on measured value of temperature difference.

Proper balance of stack effect and airflow resistance pressure gradient taking into account staircase total

leakage rate at given overpressure it is possible to obtain stable pressure distribution inside protected staircase.

Correctly designed and calibrated SAFETY WAY system fulfills literally EN 12101-6 Standard requirements

during both pressure and airflow criterion:

pressure stabilization in a range +/- 10% of nominal value;

directed airflow with minimal velocity in a range 0.75 2.00 m/s;

maximal force required to open evacuation door i.e. 100 N.

Furthermore applied devices ensures that system can change volumetric airflow rate and reduce pressure jump

resulting from opening or closing evacuation doors within normative 3 seconds.

After opening the door and in result of corresponding pressure drop inside the staircase air exhaust rate

is reduced to zero and all air supplied flows to the fire floor corridor. In case of high-rise buildings due to a large

total air leakage rate it may be necessary to apply additional fans located at technical floors in order to increase

total air supply rate.

After closing the door system automatically switches to pressure criterion involving both air supply and air

exhaust fans.

Issues connected with design and operation of the Pressure Differential Systems 1For buildings with total height up to 30 m (55 m or 65 m depending on the standard EN 12101-6, ITB 378/2002,

NFPA92A) where both stack effect and airflow resistance influence is less significant SMAY company has developed compact pressurization units of iSWAY-FC series. Owing to quite small dimensions and compact

construction iSWAY-FC units can be located in any place in the building moreover assembly and start-up

procedures are simplified. Before starting-up pressurization units it is required to ensure required air supply

rate, power supply and pressure difference measurement between protected space and the reference.

iSWAY-FC series units are manufactured in different versions depending on number and type of pressurized

spaces, location in the building (internal or external) and inspection panels access side. Technical sheets

of SMAY company pressurization units and control systems with detailed description can be found in last sections

of this Guidebook

To ensure proper operation of pressure differential system it is necessary to provide air extraction or release from

the fire floor. Otherwise dynamic changes in temperature and pressure distribution while opening evacuation

doors may result in infiltration hot smoke and gases to protected spaces and contamination escape routes.

Such problem can be detected during acceptance tests when it is not possible to obtain nominal air velocity

at evacuation door at given floor. In practice elimination of such problem after finishing all construction works

in a real building is extremely hard or even impossible. In case when air release or exhaust rate is not sufficient

pressure difference between adjacent spaces decreases gradually until pressures equalize. Airflow direction

may be opposite to the required due to local pressure raise connected with fire development. It is crucial to start

up air release or extraction installations simultaneously with pressure differential system.

Following air release/extraction installations can be listed:

gravitational openings located in building envelope such as motorized windows (susceptible to wind forces

influence);

gravitational ductworks equipped with fire dampers (to ensure proper operation large dimensions may be

required);

mechanical ventilation ductworks ensuring precise balancing of airflows and less susceptible to wind forces

influence;

smoke extraction installation.

Common mistake at concept stage of the design is to analyze given installation operation without taking into

consideration another systems in the building which may seriously influence its operation. In fact whole building

shall be treated as a set of hydraulically connected spaces in terms of airflows and pressure distribution.

Phenomena which influence pressure distribution and airflow patterns in the building are described in further

sections of this Guidebook.

It has to be noted that SMAY company solutions has been consequently tested and improved for over last two

years basing on real scale experiments and acceptance tests results moreover applied components were often

specially designed to fulfill strict requirements of standards and regulations currently in force. Main goal of the

optimization procedures was to reduce total number of necessary electronic devices and sensors such

as pressure and temperature sensors.

SMAY company except research and development activities as a first European manufacturer has voluntarily


Issues connected with design and operation of the Pressure Differential Systems 1tested described solutions in independent laboratories Institute of Industrial Aerodynamics GmbH at the Aachen

University of Applied Sciences (I.F.I.) and Building Research Institute in Warsaw (ITB). All testes have been


Legal grounds of Pressure Differential Systems design2The problems concerning protecting escape routes against smoke in buildings is defined by the Regulation of the

Minister of Infrastructure dated April 12 2002 on the technical criteria to be met by buildings and their location

(The Journal of Laws nr 75/2002 item/position 690 and later amendments). The regulation hereto defines escape

routes and states the requirements concerning their protection in case of fire.

In accordance with the Regulation's 236.1 paragraph From the rooms intended for people there should be

ensured a possibility of evacuation into a safe place outside the building or to adjacent fire zone, directly by means

of general communication routes, later named "escape routes". In accordance with further entries of the

quoted regulation, proper protection of vertical and horizontal escape routes is required:

245. In buildings:

1) low rise (LR), that hold ZL II fire zone,

2) of medium rise (MR), that hold ZL I, ZL II, ZL III or ZL V fire zones,

3) low rise (LR) and medium rise (MR), that hold PM fire zone with the fire density load 2 of 500 MJ/m or the room

with explosion hazard, encased staircases with closing doors should be applied, as well as smoke control

and smoke removal devices.

246. 2. Staircases and fire-fighting lobbies that are escape routes in high rise (HR) buildings for ZL II fire zone

and in multi-storey (MS) buildings for fire zones other than ZL IV, should be equipped with smoke control

devices.

3. Staircases and firefighting lobbies that are escape routes in high rise (HR) buildings for ZL I, ZL III, ZL V or

PM fire zones and in multi-storey (MS) buildings for ZL IV fire zone should be equipped with smoke control

devices and automatic smoke removal devices triggered by means of smoke detection system.

247. 1. In high rise (HR) and multi-storey (MS) buildings, in fire zones other than ZL IV, there should be applied

such technical and construction solutions that protect against smoke the horizontal escape routes.

Definitions, principle of operation, technical requirements for smoke protection systems (fire ventilation) are

most clearly stated by the ITB (Building Research Institute in Warsaw) Instruction 378/2002 for Designing Fire

Ventilation Installation for Escape Routes in High-rise Buildings. It states that fire ventilation (that means the

system of smoke protection) is aimed at:

counteracting against smoke and hot fire gases distribution outside the fire affected floor and along

the staircases;

enabling the evacuation of people from the endangered zone and facilitating efficient fire action by preventing

excessive visibility constraint and drop in oxygen concentration below the life hazard level in horizontal

escape routes and fire-fighting lobbies on the fire affected floor and in the staircases,

reduction of property damages owing to smoky gases activity and high fire gases temperature.

One of the technical solutions for smoke protection, which is also the SWAY case, is the pressure differential

system. Such system is the of fire ventilation installation that generates positive pressure in the staircases and

fire-fighting lobbies that are escape routes and intensively exchanges air in the protected space of horizontal

escape routes (corridors) with the constantly maintained positive pressure.


Legal grounds of Pressure Differential Systems design2The key function of pressure differential system is ensuring people's safe evacuation from the fire affected zone

with the simultaneous enabling rescue teams safe work.

The overall definition of pressure differential system is stated by the EN 12101-6 Standard: Smoke and Heat

Control Systems. Part 6: Specification for pressure differential systems Kits:

The objective of this document is to give information on the procedures intended to limit the spread of smoke

from one space within the building to another, via leakage paths through physical barriers (e.g. cracks around

closed doors) or open doors.

Pressure differential systems offer the facility of maintaining tenable conditions in protected spaces, for example

escape routes, firefighting access routes, firefighting shafts, lobbies, staircases, and other areas that require

to be kept free of smoke. This document offers information with regard to life safety, firefighting and property

protection within all types of buildings. It is necessary to determine not only where the fresh air supply

for pressurization is to be introduced into a building but also where that air and smoke will leave the building

and what paths it will follow in the process. Similar considerations apply to depressurization schemes, i.e. the

route for the exhaust air, plus consideration for the inlet replacement air and the paths it will follow. The aim

therefore is to establish a pressure gradient (and thus an airflow pattern) with the protected escape space at the

highest pressure and the pressure progressively decreasing in areas away from the escape routes.

Fig. 2.1. Pressure criterion 50 Pa according to EN 12101-6 or 20 80 Pa according to ITB Instruction 378/2002


staircase

air

re

lase

Legal grounds of Pressure Differential Systems design2

Fig. 2.3. Airflow criterion at open evacuation door according to EN 12101-6 for means of escape and firefighting.

Fig. 2.2. Airflow criterion at open evacuation door according to EN 12101-6 for means of escape.


air

re

lase staircase

staircase

air

re

lase

Fire ventilation in multi-storey buildings 3The SAFETY WAY system developed by SMAY company solves a number of problems that appear in the fire

ventilation of multi-storey (MS) buildings. This chapter presents the specifications of such buildings in terms

of selecting appropriate fire ventilation systems.

Classification of multi-storey buildings3.1

The first criterion that makes it necessary to use a proper fire ventilation system is the building's total height.

In accordance with the building regulations smoke protection system must be applied in medium-rise, tall

and high-rise buildings. In medium-rise buildings both smoke extraction and pressurization systems

are permissible. In tall buildings, in case of ZL IV residential buildings and industrial and warehouse buildings

PM, there is an option of applying smoke extraction or pressurization systems and for the remaining ZL classes

pressure differential systems shall be applied. In case of high-rise buildings it is obligatory to apply pressure

differential systems.

Fig. 3.1. Building classification in terms of the total height.

low medium-rise tall high-rise

residential building up to 4 floors

residential buildings from 4 up to 9 floors

residential buildings from 9 up to 18 floors

build

ing

tot

al h

eigh

t

12

25

55

[m]



General construction regulations indicate the necessity of using the following fire ventilation systems depending

on the building height:

in low-rise buildings that comprise ZL II category vertical escape routes shall be equipped optionally

with smoke extraction or pressure differential system;

in medium-rise buildings that comprise the ZL I, ZL II, ZL III or ZL V category vertical escape routes shall be

optionally with smoke extraction or pressure differential system;

in tall buildings except for ZL IV and PM vertical escape routes shall be equipped with pressure differential

system;

in high-rise buildings it is obligatory to apply pressure differential system protecting escape routes against

smoke infiltration.

Life Hazard category (ZL category)

Most medium-rise and high-rise buildings comprise the ZL category. These are buildings with various functions,

where their purpose may be strictly defined or they may combine different functions on their premises. In the first

case the building classification is clear and is concluded from the Regulation of the Minister of Infrastructure

dated April 12 2002 on the technical criteria to be met by buildings and their location (209 p. 2).

Table 3.1. Building classification in terms of Life Hazard category (ZL category)

ZL 1

Buildings that comprise rooms that can contain more than 50 people at the same time that are not regular users and they are not predominantly aimed at people with limited walking capabilities

ZL IIBuildings predominantly intended for people with limited walking capabilities, such as hospitals, day-care centers, kindergartens and retirement homes

ZL III Public usability buildings, unqualified for either ZL I or ZL II

ZL IV Residential buildings

ZL V Residential buildings, unqualified for either ZL I or ZL

The rules included in the regulations only describe general requirements concerning fire ventilation for each

of the mentioned categories, with special attention to ZL II and ZL IV categories. In the first case, owing to the

specific features of buildings for people with limited walking capabilities (disabled), stricter criteria for fire

protection systems are applied. Residential building are less strictly treated and for this category, even in case

of high-rise buildings, in accordance with the regulations the fire prevention installation is permissible. It is far

more difficult to precisely define requirements for a building with parts that belong to different ZL categories.

Combining in one building office, hotel and living functions is commonplace. In case as such technical solutions

should be applied for the whole building that are categorized for the least favorable building class (with the

highest requirements in terms of fire protection). Separate groups of buildings in terms of fire protection

requirements (including fire ventilation systems) are multi-storey industrial buildings. In such buildings there



is usually no obligation for legal applying special fire installations, however implementing escape routes

securities is caused by the necessity of securing the crew, especially in case of factories with a high risk of fire

explosion (e.g. pylons in heat and power plants).

2It is also obligatory to apply pressure differential system system in PM buildings if fire load exceeds 500 MJ/m

or there are rooms endangered by explosion.

Category Building heightObligatory fire

ventilation systemBuilding description

Medium-riseSmoke extraction system

Usually large cubature buildings with open galleries equipped with smoke extraction systems.

Tall and high-risePressure differential system

ZL I usually in separate zone with independent fireventilation installations





Medium-rise No requirements

TallSmoke extraction system

High-risePressure differential system



ZL I

ZL II

ZL III

ZL V

Buildings in high-risk groups in terms of fire where sleeping people may be. Such buildings are often monitored and equipped with permanent fire extinguishing devices and room doors of at least EI 30 class.

Buildings in a high-risk fire group, where sleeping people mightbe or with limited walking capabilities. Owing to this in all theZL IV high-rise buildings there should be recommendedfire protection systems in vertical escape routes and closingdevices in doors.

Usually the best monitored group of buildings, in which workingpeople are and who are able to evacuate themselves.Statistically, the lowest risk of fire endanger.

All the buildings in fire resistance class of at least "B"-practically there are no high-rise buildings (A resistance class)Owing to the specific features of ZL II buildings there is an optionof longer time for evacuation. This is why there should be designedthe zones of safe evacuation at each and every floor.

ZL IV

Table 3.2. Requirements concerning fire ventilation systems for different building categories.


Protected spaces in the buildings3.2

In buildings equipped with fire protection systems there are separate protected spaces serviced by this

installations:

- encased and door separated staircases;

- fire-fighting lobbies;

- elevator shafts;

- corridors.

Depending on the building classification and applied architectural solutions, the protected space may be one

of the spaces mentioned above, however air exhaust (release) shall take place in the lobby, corridor or fire-seized

room as well as part of the communication system in the building.

Requirements for the protected spaces in the building are listed below:

Staircases vertical escape routes which join building floors with the final exit level. In high-rise buildings where

evacuation from outside is usually limited or impossible staircases are only become only ways of escape.

Designing smoke protection and pressure differential systems in high-rise buildings special consideration shall

be given to protecting staircases as only ways of safe evacuation.

Dimensions of fire-fighting lobbies should be at least 1.4 m x 1.4 m. They have to be made in accordance to EI60

fire resistance class and ventilated, at least gravitationally. In pressure differential systems in escape routes

it is required to provide air supply installation and air transfer to the adjacent lower pressure zone or fully

functional air supply-exhaust ventilation. Fire-fighting lobbies shall be independent on the pressurization

system each lobby shall be equipped with at least one air inlet.

REMARKS

CONCERNING

STAIRCASES

CONSTRUCTION THAT

ARE VITAL IN TERMS

OF FIRE VENTILATION

SYSTEM SELECTION

staircase location in the building (internal, core section, adjacent to external wall or on the

building facade) and staircase structure (reinforced concrete, totally closed, partly or totally

glass-paned) have a significant influence on the initial pressure distribution in this space;

- architectural layout (geometry) of the staircase is particularly important for the airflow

and pressure distribution.

REMARKS CONCERNING

FIRE-FIGHTING LOBBY

Assuming minimal dimension of the lobby often doesn't allow installing required

pressure differential systems components e.g. fire dampers, air transfer dampers

or air supply shafts.

Protected spaces in the buildings3.2

Escape corridors - shall be equipped with mechanical smoke extraction or pressurization systems. Currently

selection of design solution is based on CFD simulations results depending on door opening time and evacuation

scenario.

Fire-fighting shafts for rescue operations in ZLI, ZLII ZLIII and ZL V category high and high-rise buildings that

need to fulfill requirements set in regulations. In accordance with these regulations at least one elevator in each

fire zone shall be suited to the needs of rescue team (shall meet in this scope the requirements of the Polish

standards). Access to the elevator shall lead through the fire-fighting lobbies made in accordance with the above

principles. Fire-fighting shaft should be protected with use of pressurization systems.

Pressurization in order to achieve positive pressure shall be applied to all the elevator shafts, as long as they are

not protected on particular floors with lift lobbies that meet the requirements for fire-fighting lobbies. Should

such lobbies exist, there is no obligatory need to apply pressurization systems in elevator shafts apart from the

fire-fighting shafts for rescue teams.

High-rise building as an object of hydraulic connections3.3

It is vital to identify the hazard as to the efficiency of security systems that are caused by physical phenomena

responsible for airflow and smoky gases movement in a building. It has to be noted that ambient conditions such

as air temperature or wind speed and direction may seriously influence operation of smoke protection and

pressure differential systems.

The phenomena responsible for the airflows and smoke movement in a building include: stack effect, natural

convection, thermal expansion, wind forces, airflow resistance in the staircase, piston effect, day-to-day

ventilation installation operation. It is vital to analyze listed factors together as they all shall be taken into account

when designing fire ventilation system.



Stack effect

A factor of particular importance that influences pressure distribution in high-rise buildings

and selecting methods of effective protection of escape routes is stack effect. Stack effect is a pressure

difference resulting from a difference in density between two interconnected columns of air at different

temperatures (internal air and the ambient). It results in vertical air movement in staircases, lift or installation

shafts and natural static pressure gradient between top and bottom floors. Static pressure difference

is proportional to the actual value of temperature difference and building height.

The problem can significantly influence pressure distribution in buildings over 30 m high and may often result

in faulty pressure differential system operation.

If the airflow is from down up it is normal (normal stack effect). Normal stack effect is best visible in the winter,

with low ambient temperatures. Supplying cold outside air to warm staircases causes substantial increase

of pressure gradient inside the staircase or elevator shaft. It results in low pressure zone at the bottom floors

level and high pressure zone at the top floors level.

If the air flow directed from up down it is reverse stack effect. Reverse stack effect is best visible in the summer,

with high ambient temperatures. Supplying warm outside air to cooler staircases causes substantial increase

of pressure gradient inside the staircase or elevator shaft. It results in low pressure zone at the top floors level

and low pressure zone at the top floors level.

Due to a large heat capacity of staircase or elevator shaft envelope it is not possible to stabilize pressure

distribution with intensive ventilation its cubature within reasonable time.

version 5.1.4w w w . s a f e t y w a y . p l

Fig. 3.2. The phenomena responsible for pressure distribution in high-rise buildings.

5

PISTON EFFECT6

DAY-TO-DAY VENTILATION OPERATION

1 STACK EFFECT

2 NATURAL CONVECTION

3

4 WIND FORCES INFLUENCE

THERMAL EXPANSION

AIRFLOW RESISTANCE OF THE STAIRCASE

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Convection

The phenomenon is connected with temperature difference resulting from fire. It is responsible for 'leaking'

of toxic combustion products through the leakage paths of the buildings structure to the floors above the fire

affected space. To prevent smoke infiltration at the floors above the fire floor it is possible to supply fixed air

volume via day-to-day ventilation ductwork.

Fig. 3.3. Smoke movement inside the building resulting from stack effect.


+

-

The stack effect phenomenon is not only associated with seasons of the year, faults in the work of pressurization

system but they are also visible within the time of 24 hours. Set in particular periods (e.g. one day) environment

conditions do not always guarantee that at a particular hour there will be a given pressure distribution inside

a building. Even small ambient temperature changes e.g. caused by weather breakdown may cause that in a very

short time there will appear or worsen substantial pressure stratification in the staircase, on particular floors.

In case of fire the stack effect poses two fundamental risks resulting from uncontrolled pressure distribution

in protected space:

- maximum force required to open evacuation door may significantly exceed normative 100 N value due

to the increased pressure differential across evacuation door in high pressure zone;

- smoke infiltration to the pressurized space due to the pressure differential drop in low pressure zone.

This problem is especially important since even relatively small amounts of smoke may contaminate air

in the protected space and seriously evacuation.

NEUTRAL

PLANE


Thermal expansion

It's a phenomenon that is caused by volumetric expansion (thermal) of hot gases during fire. Small pressure

change corresponds to significant temperature growth.

Wind forces

The wind outside the building generates a characteristic pressure layout around the building facade. On the

windward wall the pressure rises (positive pressure). On the opposite leeward wall the pressure drops (negative

pressure). The wind influence on the fire ventilation installation performance poses a serious problem in case

of planned (e.g. window opening) or accidental (e.g. window cracking) increased air leakage throughout the

building envelope. The resulting pressure distribution inside the building may significantly influence how the fire

ventilation installations work. Depending on the wind direction and speed, building shape as well as location

of the openings, attention must be paid to the possibility of occurring the phenomena of blowing in or sucking out

mixture of air and smoke. In buildings with complex roof shape and for high-rise buildings it is required

to determine pressure distribution in vicinity of air release or air intakes and smoke exhaust openings with a use

of CFD simulations.

Fig. 3.4. Risk of blowing in smoke onto the escape routes owing to wind influence.

version 5.1.4w w w . s a f e t y w a y . p l

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Airflow resistance of the staircase

Pressure differential system operation in the staircase always results in airflow and pressure drop in its

cubature. Staircase may be compared to the large size vertical duct transporting air with additional elements

such as stairs and landings. Pressure gradient mostly depends on air supply rate, staircase geometry and its

total height. According to measurement data typical staircase airflow resistance per single floor is in the range

3 5 Pa for class B system of EN 12101-6 European Standard. In result stabilization of pressure distribution

inside the staircase may be difficult by means of passive pressurization systems based on mechanical

overpressure dampers application. This problem is best visible in high-rise buildings moreover this problem will

occur regardless of the current ambient conditions.

Piston effect

It is a phenomenon assisting elevator car movement in the shaft. During car movement transient pressures are

produced. A downward-moving elevator car forces air out of the section below the car and into the section of shaft

above the car. In case of upward-moving car airflow patterns are opposite to the described. Elevator shaft usually

connects all floors in the building so elevator operation can significantly influence pressure distribution in the

building. The phenomenon is particularly visible in case of fast moving elevator cars. The resulting danger

is about pumping smoke by moving lifts. To eliminate this danger, at the moment of fire detection all the cars

should automatically go down and be blocked (with doors open). Fire-fighting elevator shaft shall be pressurized

in order to prevent smoke movement through the hoistway.

Fig. 3.5. Sucking in smoke due to wind forces.


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Fire ventilation systems for multistoried buildings3.4

In case of tall and high-rise buildings two principle fire ventilation systems can be listed: smoke extraction and

pressure differential systems. They differ in terms of possible technical solutions, functions they play

in a building and ensured fire safety level.

SMOKE EXTRACTION SYSTEMS PRESSURE DIFFERENTIAL SYSTEMS

GOAL: Removal of smoke and fire gases

produced during the fire out of the building

GOAL: Protecting escape routes against smoke and fire gases infiltration by achieving

fixed value of overpressure in reference to fire zone

APPLICATION: low and mediumrise buildings certain

tall buildings (PM and ZL IV only)

APPLICATION:All categories of multi-storey buildings with allocated zones of safe evacuation

EVACUATION POSSIBILITIES:No or substantial hindering

of safe evacuation

EVACUATION POSSIBILITIES:Protecting escape routes, safe evacuation

via pressurized escape routes enabled

RESCUE AND FIRE ACTION PERFORMANCE:

Enabling firefighting access below the fire source

RESCUE AND FIRE ACTION PERFORMANCE:Enabling firefighting access below the fire

source and rescue action at floors over fire source. Additionally manually triggered smoke

extraction from pressurized space

Concerns: staircases, fire-fighting lobbies and corridors

Fig. 3.6. Basic features of smoke extraction and pressure differential systems.


Pressure differential solutions offered by SMAY company4SMAY company offer covers whole range of pressure differential solutions from simple compact pressurization

units iSWAY series to complete pressure differential system SAFETY WAY . To provide highest quality of and

highest safety level in case of fire SMAY solutions include precise active control and measurement devices URBS

and operating conditions monitoring MSPU that enables visualization of selected parameters and fault

detection. It is particularly important that SMAY company goal is continuous improvement of offered solutions

and development of new complete systems i.e. car parks ventilation or smoke extraction systems.

SMAY company provides support at all stages of the project conception, design, CFD simulations, system

assembly and calibration and assistance during acceptance tests.

Please find complete data sheets of devices listed below at the end of this Guidebook.

THE SYSTEMS OF FIRE VENTILATION IN MULTI-STOREY BUILDINGS

Pressure differential solutions offered by SMAY company4Belimo Smay Control Device (URBS) is a static pressure regulation system within selected space by means

of volumetric airflow rate control that pertains an integral component of smoke and heat control system of iSWAY units and SAFETY WAY system. Device has been tested in Fire Detection, Alarm, Fire Automatics and

Electrical Installations Laboratory of Building Research Institute in Warsaw (Report No. NP.-03723/P/2009/JC),

Technical Approval ITB AT-15-8564/2011. page 51

Operating Conditions Monitoring Device (MSPU) complements SMAY company pressure differential systems

offer. MSPU can be applied to monitor data transmission circuits and operation parameters of actuating devices in simple SAFETY WAY or vast iSWAY pressure differential systems. MSPU monitoring device pertains integral

component of pressure differential systems manufactured by SMAY company. page 61

iSWAY series compact pressurization units dedicated to protect vertical and horizontal escape routes against

smoke and fire gases infiltration in case of fire.

iSWAY unit intended to protect large cubature vertical escape routes e.g. staircases and elevator shafts. Single

stage pressure regulation by means of mechanically and electrically coupled motorized multiblade dampers

equipped with fast-acting Belimo actuators. page 69

iSWAY-FC, -FCD, FCR - units ensure two stage pressure difference regulation, initial by means of frequency

inverter and precise one by means of pressure controller. Such solution ensures precise pressure difference

control and protect the system against uncontrolled oscillations resulting in pressure jumps and drops during

evacuation.

iSWAY-FC unit intended to protect staircases, elevator shafts and fire-fighting lobby. Eventually iSWAY-FC

devices can be applied to protect horizontal escape routes i.e. corridors. page 83

iSWAY-FCD unit intended to protect small cubature spaces e.g. fire-fighting lobbies in wide range of buildings.

Additionally this unit can be used to supply constant air volume to the space equipped with mechanical smoke

extraction system by means of electronically controlled air transfer regardless of evacuation door position.

Advised to apply in buildings where it is required to pressurize a number of small spaces with a use of single

pressurization unit. page 101

iSWAY-FCR pressurization of tall, high-rise and industrial buildings staircases. It is possible to design fully functional SAFETY WAY system with a use of two iSWAY-FCR pressurization units equipped with

reversible axial flow fans. Application of iSWAY-FCR units also enables intensive ventilation of the staircase and

manually triggered extraction of small amounts of cold smoke after evacuation. page 119


Idea of operation of forced airflow system SAFETY WAY 4.1

Forced airflow system SAFETY WAY - developed to protect vertical escape routes in buildings against smoke infiltration in case of fire. SAFETY WAY system shall be applied in tall and high-rise buildings staircases

and additionally in industrial buildings with large heat gains where it can operate in the ventilation mode e.g. power plants. In such application iSWAY-FCR units are equipped with additional filter modules located at

the air intake. Depending on the chosen design standard it is intended for the buildings higher than:

30 m (98 ft.) (according to the EN 12101-6 European Standard);

55 m (180 ft.) (according to French National Regulations, quoted in the ITB Instruction 378/2002);

65 m (213 ft.) (according to NFPA 92A Standard).

SAFETY WAY system consists of at least two independent pressurization units iSWAY-FCR located usually

at the top and bottom floors of the building. In buildings where such locations are not available it is possible

to place both units at the roof level and provide air supply/exhaust ductwork to the bottom floors of the staircase. Key components of SAFETY WAY system are reversible flow axial fans controlled with frequency inverters

equipped additionally with braking resistors. After initial regulation of fan capacity with frequency inverters

precise second stage control is realized by means of multiblade air dampers operating as a pressure controllers.

All air dampers applied are equipped with fast-acting Belimo actuators. All system components are controlled by

Belimo Smay Control Device (URBS). Application of electronic devices enabled development of active controlled

pressure differential system which adjust operating parameters such as air supply and exhaust rates basing

on continuous pressure difference measurement taking into account ambient temperature, wind speed and direction changes. By default integral component of SAFETY WAY system is Control Module (MS) which allows

to determine required airflow direction basing on internal and ambient air temperature difference

measurement.

Moreover application of SAFETY WAY system doesn't require any additional pressure control devices such

as mechanical barometric dampers. In case when such device locations are not possible it is necessary

to provide air inlets/outlets in the top and bottom zones. Whole year can be divided into three conventional

periods depending on standard internal and ambient temperature difference:

winter period when ambient temperature is lower than air temperature inside the building. During this

period due to the stack effect high pressure zone at the top floors and low pressure zone at the bottom floors occur in reference to the barometric pressure. iSWAY-FCR pressurization units supply air to the bottom

floors zone and exhaust it from the top floors zone.

summer period when ambient temperature is higher than air temperature inside the building. During this

period due to the stack effect high pressure zone at the bottom floors and low pressure zone at the top floors occur in reference to the barometric pressure. iSWAY-FCR pressurization units supply air to the top floors

zone and exhaust it from the bottom floors zone.

Natural pressure gradient value is proportional to actual value of temperature difference and total building

height.

Interim period when internal and ambient air temperatures are approximately equal. During this period

no pressure gradient should occur. Significant problem in terms of pressure differential design is pressure

drop connected resulting from staircase airflow resistance.



Idea of operation of SAFETY WAY pressure differential system for winter and summer periods is presented

below. For interim period system operates in similar way to the winter period with reduced airflow rates.


iSWAY-FCR iSWAY-FCDiSWAY-FC

iSWAY-FCD

Fig. 4.1. Pressure distribution stabilization inside

heated staircase during winter period


Fig. 4.2. Pressure distribution stabilization inside

air-conditioned staircase during winter period




iSWAY-FCD

Fig. 4.3. Example of SAFETY WAY system operation

during an airflow criterion

Except pressure criterion SAFETY WAY system

ensures possibility of airflow criterion can be fulfilled

in terms of required air velocities at open evacuation

doors. Opening evacuation door results in immediate

pressure drop inside the pressurized space. In such

situation exhaust airflow rate is reduced to zero and

air supply rate is increased to the nominal value

required to achieve nominal air velocity at given

evacuation door.

Application of compact pressurization units of iSWAY-FC series allowed to simplify SAFETY WAY system

structure and reduce overall price of complete pressure differential system. Additionally number of independent

components has been reduced as well i.e. control system components and wiring.

During airflow criterion in high-rise building staircase depending on selected system class and total air leakage

rate additional air supply units may be required to provide stable pressure distribution all along the staircase

as well as nominal air velocities at open evacuation doors. By default it is assumed to provide one air supply inlet per each ten floors of the staircase. Additional air volume is supplied with iSWAY-FCD unit with pressure

controller calibrated in that manner to maintain 25-30 Pa of pressure difference between protected space and

the reference.


Fig. 4.4. Pressurization of high-rise building staircase with SAFETY WAY system with additional air supply unit iSWAY-FCD application.


KWP-o - fire damper open, KWP-z - fire damper closed x - In case of design in accordance with EN 12101-6 European Standard it is required to apply twin air intakes system.

Fire-fighting lobbyCorridor Staircase Fire-fighting lobbyCorridor Staircase

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PLEASE NOTE: Proper operating parameters such as fan capacities and air inlets/outlets location for SAFETYWAY system are provided by SMAY company basing on building design details, pressure

differential nominal operating parameters. For high-rise buildings exact values of listed parameters are

determined basing on CFD simulations results.

To place an order for complete SAFETY WAY system design it is necessary to provide:

- dimensioned views and sectional views of the staircase;

- overall description and schematic diagram of pressure differential system in analyzed building;

- dimensions and locations of air supply shafts;

- pressure differential system operating conditions and nominal parameters required by fire protection

expert;

Ordering party receives complete CFD calculations report in printed and electronic version as well

as guidelines required at all stages of the design.

SAFET WAY system application in industrial buildings (PM)4.2

Pressure differential systems design in high-rise building may become a problem but the real challenge both for

the designer and most of all manufacturer is the variety of industrial buildings with a range of different requirements. SAFETY WAY system may be also safely well applied in buildings where due to the technological

process increased heat gains may occur. In such application SAFETY WAY system operates in two modes:

standard mode when protected space is continuously ventilated with a fixed value of overpressure

maintained. This ensures both heat gains removal (temperature control) as well as protection against dust contamination. iSWAY-FC or iSWAY-FCR pressurization units are additionally equipped with Filtration

Modules (FM) located at the air inlet duct with pressure controllers allowing to determine dust filter

condition;

fire mode when protected space is pressurized in order to achieve fixed nominal parameters terms

of pressure difference and air velocities.

Due to the construction applied iSWAY-FC series units can be used in constant operation mode. After receiving

Fire Alarm Signal (SAP) from fire alarm control and indication equipment devices automatically switches to fire

mode. In this mode air is supplied to the staircase or other protected spaces via additional ductwork branch

omitting Filtration Module (FM).


Pressurization of fire-fighting lobbies 4.3

An example of industrial buildings application of SAFETY WAY system are staircases intended to ensure safe

evacuation from central boiler plants buildings. Such staircases are adjacent to the room where power boiler

is located where large heat gains and dust emission occur. Due to its structure and special control algorithms SAFETY WAY system ensures constant pressure difference between boiler room and the staircase regardless

of boiler operation mode and ambient parameters. Additionally in such applications all fire-fighting lobbies shall

be pressurized since they are all adjacent to the single fire zone.

Fire-fighting lobbies connect horizontal and vertical escape routes. Nominal value of overpressure inside the

lobby depends on the selected overpressure inside the adjacent staircase e.g. pressure differential of 5Pa

between the staircase and the lobby. According to the European Standard it is assumed that fire can occur only at

one floor at given time. Fire-fighting lobby is pressurized at fire floor only. In special cases simultaneous

pressurization of all fire-fighting lobbies may be required. Air is supplied to all lobbies via single shaft.

For standard pressure differential system balancing of such installation may be difficult. Pressurization system

dedicated to fire-fighting lobbies operates in two modes analogical to the staircases (pressure and airflow

criterion).

Buildings currently designed are often equipped with mechanical smoke extraction system in order to protect

horizontal escape routes. Since according to the European regulations it is forbidden to apply frequency inverters

to control smoke extraction fans capacities it is required to provide constant air volume supplied to the corridors

to control pressure difference across evacuation doors regardless of their position. SMAY company has

developed solution enabling electronically controlled air transfer from the fire-fighting lobby to the corridor.

Each fire-fighting lobby is equipped with independent set of two mechanically and electronically coupled

pressure controllers with fast acting Belimo actuators NMQ24A-SRV-ST. Idea of operation is quite simple both

air dampers operates backward in that manner that opening angle of each air damper is inversely proportional.

Air damper located in the fire-fighting lobby operates as a pressure controller. While evacuation doors are closed

excess air is transferred to the corridor via the by-pass damper and the pressure control damper is almost fully

closed. After opening the door by-pass damper closes and pressure control damper opens and required nominal

air volume is supplied to the corridor through evacuation door.


Fig. 4.5. Idea of operation of electronically controlled air transfer during pressure criterion (no evacuation)


Optionally SMAY company offers standard solution based on mechanical air transfer dampers located in the wall

between fire-fighting lobby and the corridor. Often due to the limited size of the lobbies it is not possible to apply

mechanical air transfer dampers in the wall due to the large size required especially for class B pressure

differential system according to the EN 12101-6 European Standard.

Advantages of electronically controlled air transfer:

reduction of air transfer elements dimensions;

precise control of pressure difference across evacuation door;

constant monitoring of pressure differential system operating parameters i.e. pressure difference

and possibility of failure detection.

NOTE:

In case of systems designed in accordance with EN 12101-6 European Standard it is advised to apply

electronically controlled air transfer due to the small nominal pressure difference between fire-fighting lobbies

and the staircase. In case of systems designed in accordance with ITB Instruction 378/2002 mechanical air

transfer dampers may be applied.

Basing on the practical experiences resulting from acceptance tests SMAY company recommends special

calculation methodology that assumes air supply rate to the fire-fighting lobby shall be sufficient to obtain

nominal air velocity at the door between protected lobby and the corridor e.g. 2.0 m/s. Such approach allows

to eliminate common problem with balancing airflows between hydraulically connected pressurized spaces.


0Pa

50Pa

45Pa


Fig. 4.6. Idea of operation of electronically controlled air transfer during airflow criterion (evacuation)

Fig. 4.7. Schematic diagram of fire-fighting lobby pressurization with mechanical air transfer to the corridor

in accordance with ITB Instruction 378/2002 (p = 20-80Pa)max


6Pa

2,0 m/s

+

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+


In case when fire-fighting lobby is connected to the corridor with two doors it is recommended to apply double

electronically controlled air transfer. Solution presented below ensures possibility to obtain nominal airflow at

both doors e.g. 2.0 m/s. Additionally enables precise predefined pressure differential control across the

evacuation door.

Fig. 4.9. Idea of operation of double electronically controlled air transfer during airflow criterion (evacuation)


Fig. 4.8. Idea of operation of double electronically controlled air transfer during pressure criterion (no evacuation)

6Pa2,0 m/s

2,0 m/s

0Pa

50Pa

45Pa

0Pa

Air exhaust/release systems5So that the smoke prevention systems can work properly in high-rise buildings, it is indispensable to implement

the installation of air release. In case of work of the installation that pressurizes the zone of overpressure, with

the simultaneous lack of installation that carries away or removes smoke, both smoke and fire gas shall be

blown into the protected space after the door that separates this space has opened. In result escape routes may

be cut off. Besides, smoke and other toxic combustion products may spread at a large distance from the fire

source.

Fig. 5.1. Mixture of air and smoke flow

in the situation

of pressurization without

providing air release path.

The installations of air reception should work automatically at the moment the system of pressurization starts

to work. It means that on the floor seized by fire a flow needs to be opened that will direct the smoke-filled air

directly or with the use of smoke shafts outside the building. The following solutions may be applied as the

installations of air reception:

Pivoting windows or other openings in the inside walls, equipped with actuators they need to be installed

on each floor, in each separate room that is connected with escape passage. Should the staircase exit lead to the

open-space room, it is possible to limit the number of pivoting windows. Correctly selected windows active area is

enough to fulfill the requirements concerning the air flow requirements. The conditions for the use of pivoting

windows as a system of air reception include: they should be placed in the area adjacent to the one protected by

overpressure and equip windows with certified actuators that enable their automatic opening with the

simultaneous triggering of the pressurization system. This is a fairly easy solution. It does not require technical

space that is necessary to make the installation for smoke reception. The wind forms a serious limitation in the

use of pivoting windows and it is especially dangerous for high rise buildings. Bad weather conditions (opening

windows to windward) may result in blowing the smoke inside the building, making the pressurization to no avail.

High negative pressure that is formed on the leeward surface of the wall in the presence of strong wind may also

seriously disturb the pressure system inside the building. A solution to this problem may be installing pivoting

windows on two different walls of a building (the so called doubling the system) and proper control set depending

on the current wind direction (anemometer).


SMOKE AND FIRE GASES

Air exhaust/release systems5Gravitational ducts for air exhausting (equipped with fire dampers)

The air intake is secured with motorized fire dampers. Each fire damper is normally closed. When the fire

ventilation system turns on, the fire dampers on the fire-seized floor open, whereas the remaining fire dampers

stays closed. The gravitational ducts make use of the overpressure triggered in the area of smoke reception

by the work of installing security measures against smoke. This phenomenon is additionally supported by

higher pressure that appears together with the air that flows through the open door between the staircase and

the escape passage. Gravitational ducts should be mounted in vertical position on all the floors (just like in case

of the ducts of gravitational ventilation). It is a simple and cheap solution; it enables carrying away smoke from

space, where the method of fire breakout through windows or smoke dampers is hard or even impossible

to realize. The weak point of a gravitational duct is its large intersection owing to large air flow required (the

calculation was made based on air balance that gets into the zone of smoke removal from the area protected

by overpressure). Apart from that, the ducts needs to be placed directly in the zone where smoke reception takes

place. A solution as such requires neat finishing of inside surface to limit resistance of flow and it is limited to high

buildings.

The ducts of mechanical smoke reception (that exhaust air and which are equipped with certified fans

for smoke exhaust)

The air intake to air exhaust ducts takes place through the fire dampers in accordance with the rule that was

described in the previous point. When the pressurization of the areas of the buildings protected by overpressure

commences, fire dampers get open on the fire-seized floor, as well as the fans for smoke exhaust. Capacity of the

fans should be calculated based on air balance that gets on the building floor from the area of overpressure.

The system works properly on condition the solutions are applied that ensure the constant air flow on the fire-

seized floor from the area protected by overpressure, no matter what the current position of emergency door is.

Both the balanced supplied and removed volumes allow avoiding the phenomenon of negative pressure in the

zone where smoke ventilation works, which significantly facilitates the regulation of parameters of the work

of pressurization installation. The described effect may be achieved by applying different kinds of air transfer

from the pressurized zone to the zone of smoke exhaust.

Smoke extraction installations

The smoke extraction installation should first and foremost absorb all the smoke that is produced during fire and

remove it outside the building. Last but not least, the smoke removing installation should on horizontal escape

routes separate vertically between the zone of hot smoke and the 'clean' zone where people are.


Air exhaust/release systems5


Tab. 5.1. Smoke extraction systems benefits and drawbacks

Smoke extraction system Location Benefits and drawbacks

Pivoting windowsor other openingsin building envelope

External walls in therooms directlyadjacent to theoverpressure protectedzone.

Benefits:- low investment costs;- easy assembly;- high smoke removal efficiency.Drawbacks:- highly sensitive to weather conditions.

Gravitational smokeremoval ducts

In the area directlyadjacent to theoverpressure protectedzone

Benefits:- low assembly cost;- simple construction;- low sensitivity to weather conditions.Drawbacks:- large technical zone required;- neat assembly indispensable;- no option of connecting horizontal ductworks.

Mechanical smokereception ducts

In any place on thepremises of a building the inlet in the zonedirectly adjacent tothe overpressure zone

Benefits:- no limits as to the building's height;- smaller need for technical space than in case of gravitational ducts- high smoke removal efficiency;- option of connecting horizontal ductworks;- possibility of using general ventilation installation on condition it is specially made.Drawbacks:- additional cost of smoke control fans with the guaranteed power supply and wiring;- high assembly costs;- necessity of precise air stream balancing.

Mechanical smoke extractioninstallations

In any place on thepremises of a building smoke removalinstallation in escapepassages.

Benefits:- there is no limit as to the height of the building;- high efficiency in smoke removing;- possibility of connecting horizontal ductworks- possibility of using general ventilation installation on condition it is specially made.Drawbacks:- negative pressure may be created in the escape passage versus the protected;- high investment costs.

Current procedures of testing pressure differential kits6

EN 12101-6 European Standard since it was introduced stirs up controversies both in Poland and other European

countries. Many of serious issues has not been well defined and explained. Special attention has been paid to the

functional requirements that pressure differential systems shall fulfill but issues connected with detailed design

procedures as well as with testing key components and whole sets of devices has not been described at all. Since

no official procedures has been developed and introduced 12101-6 European Standard couldn't been recognized

as an official reference document in terms of issuing Technical Approval for a complete pressure differential

system by certifying units (notified bodies) in each country.

This problems have been identified by European Committee for Standardization (CEN) TC191/SC1. Currently

within Working Group WG6 works are in progress in order to prepare novelized versions of EN 12101-6 and EN

12101-13 European Standards. Both documents are under development and they should be officially issued

by 2012.

In novelized EN 12101-6 European Standard special attention was paid to the issues connected with laboratory

tests of pressure differential systems. Special unified procedure has been developed both for mechanical

(passive) and electronic (active) pressure differential kits. All tests so far was carried out in independent

Laboratory of Institute of Industrial Aerodynamics GmbH at the Aachen University of Applied Sciences (I.F.I.).

All Working Group WG6 members have agreed that fundamental issue of pressure differential system

application is to ensure normative parameters regardless of the actual ambient parameters and building height.

As a result additional requirements has been also defined as regards of acceptance test procedures with special

consideration of high rise buildings.

Taking into consideration actual legal status and in order to provide highest possible quality of offered solutions SMAY company as a first European manufacturer has tested iSWAY-FC and SAFETY WAY according to the latest

version of normative testing procedure. Performed test have confirmed that SMAY company solutions can

literally fulfill strict EN 12101-6:2007 European Standard requirements.

Testing procedure schedule:

Functionality tests 20 cycles pressure regulation accuracy and time of achieving 90% of new volumetric

airflow or reducing pressure difference to 60 Pa or less;

Reliability tests 10 000 cycles of opening and closing evacuation doors;

Durability test 20 cycles in order to determine mechanical wear of system components and influence

of long-time operation at functional parameters values;

Oscillations test 10 series 20 cycles each in order to determine stability of pressure regulations during

different stages of evacuation.

Functionality and reliability6.1



3SAFETY WAY system results nominal fan capacity 16 000 m /h, nominal pressure difference pN = 50 Pa

Test type pN [Pa]

Time required to achieve 90% of new

volumetric airflow [s]

Time of reducing pressure difference

to 60 Pa or less [s]

GRADE

FUNCIONALITY 45 2.3 1.8 PASSED

RELIABILITY - PASSED DURABILITY 45 2.5 2.5 PASSED

OSCILLATIONS - PASSED

Test Type pN [Pa]

Time required to achieve 90% of new

volumetric airflow [s]

Time of reducing pressure difference

to 60 Pa or less [s]

GRADE

FUNCIONALITY 50 1.4 0.3 PASSED

RELIABILITY - PASSED DURABILITY 50 1.0 0.2 PASSED

OSCILLATIONS - PASSED


3iSWAY-FC compact pressurization unit results nominal fan capacity 15 600 m /h, nominal pressure difference

pN = 45 Pa

Laboratory tests that were carried out have confirmed that properly designed and configured electronically

controlled pressure differential systems can literally meet all requirements described in EN 12101-6 European

Standard. Moreover modern components of pressure regulation system meet strict requirements in terms

of reliability ensuring high safety level in case of fire.

Thanks to the carried out tests, research project realization and practical experience gathered during

acceptance tests SMAY company can be described as one of the leading European manufacturers of pressure

differential systems.

It shall be noted that the best designed pressure differential systems require professional assembly and on-site

calibration to provide declared parameters. It shall be noted that the final and the most important test for each

and every pressure differential system shall be acceptance testing carried out in accordance with normative

procedure. Acceptance testing results shall be treated as the most valuable recommendation of pressure

differential system.

Fig. 6.1. The title page of I.F.I. official test report of iSWAY-FC compact pressurization unit

Fig. 6.2. The title page of I.F.I. official test report of SAFETY WAY system



Electronic components tests6.2

Additional components of Belimo Smay Control Device as a basic pressure regulation component tests were

carried out in Fire Detection, Alarm, Fire Automatics and Electrical Installations Laboratory of Building

Research Institute in Warsaw (Report No. NP.-03723/P/2009/JC) covered tests of resistance to electromagnetic

compatibility interferences, ESD static electricity discharges, influence of electromagnetic field, strength

and resistance to environmental, climatic and mechanical influence such as vibrations, surges and single

strokes.

Table. 6.1. List of tested parameters of Belimo Smay Control Device (URBS)

As regards of pressure differential systems it is crucial to test components of pressure regulation system.

To ensure proper operation of offered solutions SMAY company has tested URBS together with multi-blade air-

damper operating as a pressure controller. It shall to be noted that at the moment there is no normative

requirement to carry out any tests of barometric dampers which are one of the most popular pressure regulating

devices. It is possible that this situation will change in the near future and as a result testing procedure for this

component will be developed and introduced.

Performed lab tests have confirmed that Belimo Smay Control Devices (URBS) fulfill all the requirements set

for electronic pressure control devices applied in fire protections systems.

Basing on mentioned tests results Building Research Institute in Warsaw I.T.B. has issued the Technical

Approval ITB AT-15-8564/2011 confirming all operating parameters declared by SMAY company was issued.

lp. Tested feature Attach. 2 The Journal of Laws nr 143/2007 item 1002

Result

1 Marking and identification p. 12.1.1.1 PASSED

2 Resistance to vibrations p. 12.1.5.b PASSED

3 Strength to vibrations p. 12.1.5.c. PASSED

4 Resistance to cold environment p. 12.1.5.d PASSED

5 Resistance to hot and humid environment p. 12.1.5.e PASSED

6 Mechanical resistance to single strokes p. 12.1.5.f PASSED

7 Operating parameters at the corrosive environment

p. 12.1.5.g PASSED

8 Resistance to the static electricity discharges

p. 12.1.5.h PASSED

9 Influence of electromagnetic field p. 12.1.5.i PASSED

10 Resistance to electrical transient state series

p. 12.1.5.j PASSED

11 Resistance to impulsive waves p. 12.1.5.k PASSED

12 Resistance to current decays p. 12.1.5.l PASSED

13 Resistance to electromagnetic interference p. 12.1.5.m PASSED

14 Resistance to supply decay changes p. 12.1.5.n PASSED



Electronic components tests6.2

Official report documents of performed tests are available to download from SMAY company official website

www.smay.pl

Fig. 6.3. Title page of the Technical Approval ITB AT-15-8564/2011


CFD simulations 7CFD simulations are often used to evaluate effectiveness of both smoke extraction and pressure differential

systems. Last years have brought significant changes in this field due to the improvement of calculation

capabilities of available machines. This enabled more precise analysis of vast installations in terms of heat and

mass transfer.

Documents

Smay Pressure Differential Systems Guidebook v514-En