Hrb electromech,111116

Moustafa M. Elsayed, Doha (12/9/2006) 1

What you need to know about Designing

Electro-Mechanical Systemsfor

High-Rise Buildings

By

Dr. Moustafa M. Elsayed

[email protected]


Contents

• Definition of a High-Rise Building

• Introduction

• Design Requirements

• Stack Effect

• Core Design, Location and Components

• Floor-to-Floor Height & Raised Floor

Option

Moustafa M. Elsayed) 3

Contents

• Electric & Communication

Closets

• Building Orientation

• Insulation and Heat Stores

• Fire Scenario

• Fire Fighting Strategy


Super High Rise

Building

Shimizu Super Highrise

(SSH)

Shimizu Corp. (Japan)


Definition of a High-Rise Building



The International Building Code (IBC 2000)

and the Building Construction and Safety Code,

NFPA 5000TM-2002, define high-rise buildings

as:

A structure more than

22 m (75 feet ) high



A Strategy for Dublin Building Height, proposed four height thresholds

Low-rise - up

to 15m

Mid-rise - 5 to

50m

High-rise -

50 to 150m

Super high-

rise - above

150m



The ASHRAE Technical Committee for

Tall Buildings, TC 9.12

one whose height is greater than 300 feet

(91 m).



The Council on Tall

Buildings and Urban

Habitat (CTBUH)

one in which the

“tallness” strongly

influences planning

design or use.



The General Services Administration (GSA) in USA sponsored the “International Conference on Fire

Safety in High-Rise Buildings” in Warrenton, Virginia, on April 12, 1971. That conference arrived at

a more complex and more flexible definition that is appropriate. It stated:

A high-rise building is one in which emergency evacuation is not practical and in which fires must

be fought internally because of height.


Introduction

The tall commercial

office building only

became possible

through the

invention of the

elevator safety

braking system by

Elisha Graves Otis in

1853.


Introduction

• High-rise = high-risk

• All high-rise building design will require

performance-based (engineered) fire and

life safety design

• The fire resistance of the structure, to

larger and longer duration fires, will be a

consideration


Introduction

• Every year there are about 7,000 fires that

break out in high rise office buildings

causing deaths, injuries and millions of

dollars in fire damage. Most of these could

be eliminated if everyone practiced good

fire prevention on the job and planned

ahead for a fire emergency.

• Construction material and fire proofing

material will get extra attention


Design Requirements

Symbols of power, prestige, wealth,

success, and national pride.

Buildings, and their occupants, as safe and

secure as possible.


Design Requirements

• Life safety

• Smart security

• More bandwidth, smarter buildings.

• More hours of operation, along with more

electrical capacity, fiber optic access, and

heating and air conditioning capacity.

• Energy efficient building


Design Requirements

• Efficient vertical

transportation

• Smart mechanical systems

• Building infrastructure must

be well planned to attract

tenants

• Easy upgrades and retrofitting

to accommodate future

technologies.


Stack Effect

Stack

effectReverse

stack

effect


Stack Effect


Stack

Effect


Stack Effect: Problems

Elevator doors’ failure to close

properly


Stack Effect: Problems

Heating / Cooling Problems


Stack Effect: Air Entry Points

• Entry doors & doors that

open to truck docks

• Any outside air intake or

exhaust

• Louvers that are provided in

the building


Stack Effect: Air Entry Points

• Overhangs in the construction

with light fixtures that are located

immediately above the ground

level and are not properly sealed

against leakage.

• and any possible small fissures in

the exterior wall itself.


Stack Effect: Internal Passages

• Fire stairs

• Elevator shafts

• Mechanical shafts for ducts and

piping

• Any other vertical penetrations

that exist at the edge of the

floor slab at the exterior wall or

for pipes.


Means to Minimize Stack Effect

• Use tight exterior wall

• Vestibules or air locks for loading docks,

with good door seals, or use of revolving

doors

Minimizing Infiltration from Outside


Minimizing Infiltration from Outside

• Use Supply at least 5% outside air than exhaust to ensure pressurization tight exterior wall

• Close all shafts & seal all penetrations


Means to Minimize Stack Effect

Minimizing Internal Air Flow

Using doors at the

entry of elevator

banks

Stairs are to be

interrupted with

doors


Core Design

•The core design should meet the

needs of the occupants while

also simplifying the provision of

mechanical and electrical

services to the occupied floor

•The cost of the core and its

content can be substantial.


Core Design

• The configuration of the core should be

arranged in the tightest area possible,

resulting in the most efficient possible

use of the floor.


Core Location

Central Core

• Maximum flexibility in the architectural

subdivision of the floor

• Potential to improve the distribution of air-

conditioning ducts

• Simplify the construction of the building


Core Location

Multiple Cores

• In buildings with very large floor plates, multiple cores may be necessary to reduce the travel distance to stairs or toilets.

• A cost disadvantage of multiple cores is the potential need for additional elevators, although this is not always necessary.


Core Components

• Fire stairs

• Vertical transportation elements: passenger

elevators and one or more service or freight

elevators

• Toilet rooms for both the male and female

• Electric closets

• Communication closets for multiple

telecommunication providers


Core Components

• Local fan rooms or large supply air and

return air shafts

• Shaft space for other HVAC risers, such as

toilet exhaust, general exhaust, or dedicated

smoke exhaust risers and possibly kitchen

exhaust risers


Core Components

• Space for risers for the piping of the HVAC

system and plumbing system as well as riser

space for electrical distribution cable and

distribution cable for the building

management and fire alarm systems.


Core Area

• The definition of an efficient core is not simple in that the percentage of the gross area that will be used is very much a function of the size and the usage of the floor.

• For example, on larger floor plates, i.e., those with areas greater than 20,000 gross ft2 (1,800 gross m2), it is a core that often will take less than approximately 15 to 20 percent of the total floor area of a given floor.


Core Area

• If a floor grows beyond a certain size or has

internal loads with high cooling requirements

it can become necessary to add a second local

floor air-handling unit and fan room, which

will cause a reduction in the usable area.

• Moreover, on smaller floor plates, the core

may take as much as 30 percent of the total

floor area.


Example of a Core Design


Floor-to-Floor Height

The overall cost of a tall building is affected by the floor-to-floor height of the individual floors.



An increase in the floor-to-floor height will increase the surface area of the skin of the

building, the length of the vertical structural elements as well as all of the building’s other vertical elements, such as shaft enclosures,

HVAC, plumbing, electrical power distribution and telecommunication risers,

elevator components, stairs, and the length of the interior partitions.



• Where zoning regulations exist that limit the bulk and height of a building, a small increase in the vertical dimension of each floor may result in fewer floors in the developed building.

• The final floor-to-floor height of the office occupancy floors of any building will involve decisions by the owner, architect, structural engineer, and both the HVAC and electrical engineers.


Raised Floor Option

The need to satisfy the expanding and continually changing electronic needs in the

tall commercial building has forced consideration of the inclusion of a raised

floor to handle the horizontal distribution of both power wiring and information

technology cabling, which includes both the telecommunication cabling and any

interconnection of personal computers, printers, and the like.


Raised Floor Option

Typically the raised floors in

general office occupancies will

be between 4 and 6 inches (100-

150 mm) above the concrete slab

when the raised floor is used

exclusively for the distribution

of power wiring and

information technology cabling.


Raised Floor Option

• Floor tiles are included above the slab to provide the walking surface in the office space, which in turn are covered by carpet tiles of the same size as the floor tiles.

• The carpet tiles and then the floor tiles can easily be lifted to provide the needed access to allow modification of the wire and cable as changes evolve in the needs of tenants.


Raised Floor Option

One cost benefit that resultes to projects using a

raised floor exclusively for wire and cable

distribution is that neither the wire nor the cable

installed within the raised floor cavity need be

plenum rated or installed in conduit.

Nonetheless, the application of raised floors with

under-the-floor air-conditioning distribution

systems is becoming more common with the

increased use of raised floors.


Raised Floor Option

The use of a raised floor allows the

relocation of electric outlets and

information technology connections at a

relatively low cost when compared to the

cost of these relocations without a raised

floor.


Raised Floor Option

The inclusion of the raised floor will increase

the floor-to-floor height, but the integration of

a raised floor with an under-floor air-

conditioning distribution system may

minimize, if not eliminate, the increase in the

floor-to-floor height for a given project.



Conclusion


Floor-to-Floor Height: Conclusion

• The floor-to-floor height of a tall commercial office building can usually be of 3.8 m 4.1 m.

• See Figure 1-6.

• The space from the bottom of the ceiling to the top of the slab of the floor above is 1.2 m.


Floor-to-Floor Height: Conclusion

• This 1.2 m space would contain the lighting fixtures, ducts, sprinkler piping, and structural steel system supporting the slab.

• An increase (or decrease) in any of the elements shown in this figure will result in an increase (or decrease) in the floor-to-floor height.


Electric Closets

• Location: to permit diverse routing to any area of the floor to meet the design criterion, in watts per square foot.

• There are limits to the distance that the floor distribution cable can be extended on any given floor without a cost penalty.


Electric Closets

• On a floor in excess of approximately 25,000 ft2 (2,400 m2), more than one electric closet will be required to serve that floor.

• On floors smaller than 25,000 ft2 (2,400 m2), a second closet may still be included to meet the possible future expansion needs


Communication Closet• The communication closet has gone through

a major series of changes over the past decade.

• Originally the closet was called a telephone closet, but that terminology is rarely used today.

• The appropriate terminology is “telecommunication,” “communication,” or “information technology” closet.


Communication Closet

• Traditionally, the closet contained the vertical telephone riser cables that in turn connected to telecommunication terminal blocks from which the horizontal runs on the specific floor were extended by the telephone company to the user’s phone.

• However, that was in a time when there was only one telephone company and no such thing as a computer.



The communication risers may not be installed

during construction, just the riser space and

empty sleeves in the communication closet,

with the empty risers being filled as specific

tenants request specific telecommunication

providers for their space.



In the below-grade levels, space will be

needed for multiple points of entry from each

telecommunication provider to allow its

service to be brought to two separate service

rooms from at least two different streets to

ensure continuity of service under any

possible emergency contingency.


Building Orientation

• Tall buildings are exposed to

the full impact of external

temperatures and radiant

heat.

• The overall building

orientation has an important

bearing on energy

conservation.


Insulation and heat stores

• Good thermal insulation of the building skin reduces heat transfer, both from solar gain and loss of coolness from the inside.

• A second skin (a rain wall) can be built over the inner wall with an air gap in between.

• Structural building mass may be used to store heat.


Insulation and heat stores

• In temperate climates, structural and building mass can absorb solar heat during the day and release it at night. A water-spray system on hot facades promotes evaporation and therefore cooling.

• Also in temperate regions, solar windows or a solar-collector wall can be located on the outer face of the building to collect the sun's heat.


Fire Scenario :

One Meridian Plaza Fire

• In 1991 a fire on the 22nd

floor of the 38-story Meridian

Bank Building (Philadelphia)

took place for more than 19

hours.

• It was the largest high-rise

office building fire in modern

American history


Fire Scenario :

One Meridian Plaza Fire

• Completely consuming eight

floors of the building

• Fire was controlled only

when it reached a floor that

was protected by automatic

sprinklers.


Fire Scenario : VENTING

• Sealed or locked windows (High-rise buildings may be considered windowless buildings)

• Risk of venting by breaking thick glass windows


Fire Scenario : VENTING

• Large volumes of heat and

smoke generated by the

fire become trapped in the structure.

• This giant smoke cloud, spreads throughout the sealed high-rise building.


Fire Scenario : Stack Effect

• The so-called "stack effect" causes smoke

to spread up or down many floors during

a fire in a high-rise.

• The uncontrollable smoke movement

caused by the stack effect is another

reason window venting is ineffective

during a high-rise fire.


Fire Scenario : HVAC SYSTEMS

• HVAC systems in some HRB are not fire-resistive

• Ducts, shafts, and poke-through holes penetrate fire-resistive floors, walls, and ceilings

• A high-rise hotel fire in Las Vegas, Nevada, spread fire and smoke through the central air-conditioning system and killed 85 people in rooms on upper floors.



• The air system was not equipped with smoke detectors arranged to shut down the system during an emergency.

• The fire dampers-shutters designed to stop spread of fire in ducts and shafts of the air-conditioning system--did not close properly.



• Smoke, heat, and flame were pumped

throughout the so-called fire-resistive hotel by

the air-conditioning system.

• Firefighter's battling a fire in a high-rise

building depend on the building systems for

success in extinguishments.


Fire Scenario : Service Systems

• The elevator system must take them, tools, and equipment up to the fire.

• The standpipe system must provide water pressure and volume to the upper floors.


Fire Scenario : Service Systems

• A building communication system must

allow fire department firefighting radio

transmission in these steel skyscrapers.

• If any of these building systems fail or

are not present, firefighters will be

unable to extinguish the fire.


Fire Scenario : Elevators

It is important to note that elevator shafts,

like stairwells, are vulnerable to smoke

contamination as well.


Fire Scenario : Elevators

Due to both the Stack effect and the Breaking-of-the-Seal effect, smoke penetrates into both the elevator carriages and shafts during a fire. Additionally, when elevator carriages are forced to make stops on smoke filled floors, both the elevator shaft and the carriage itself can quickly become contaminated beyond usable limits.


Fire Fighting Strategy



• At a low-rise building fire, strategy can be

to extinguish the fire and evacuate the

people at the same time.

• HRB people evacuation

• HRB defend in place strategy


Impacts on Fire Engineering

• Performance of people trapped in a burning

high-rise building

• Firefighting strategies for HRB:

�from inside stairways.

�an interior attack.


Impacts on Fire Engineering

• Firefighters must extinguish the fire using

handheld hose streams advanced through heat

and smoke from an inside stairway. If this

method fails, there is no alternate plan. An

outside attack is not an option.



• A defend-in-place strategy depends on two factors: that the building has the ability to contain fire to a particular area and that the occupants will obey the fire chief's instruction to stay in place.

• Neither of these assumptions is necessarily true. High-rise buildings are not fire resistive, and people leave the high-rise buildings during a fire regardless of instructions to do otherwise.

• Experience showed that "the 'defend-in-place‘ strategy does not exist."



• The only real fire protection for a high-rise

building is

�an automatic sprinkler

�a smoke-removal system


Smoke Management: Objectives

• To remove smoke from the area within which a fire has developed

• To maintain smoke-free areas that will allow the occupants to exit the building without being subjected to the smoke generated by the fire.


Methods of Smoke Control

Objectives

�To control the movement of smoke in case of

fire in order to facilitate the protection of the

occupants and properties in the building.

�To help firefighters to accomplish their job.



Compartmentation

Dilution

Pressurization


Compartmentation

�Compartmentation is to use barriers with

sufficient evidence to remain effective

throughout a fire exposure. These barriers

provide protection against fire spread.

�Barriers like walls, partitions, floors, doors,

....etc, provide some level of smoke

protection to spaces remote from the fire



Dilution Remote from Fire

� This is used to maintain acceptable gas and

particulate concentrations in a compartment

subject to smoke infiltration from an

adjacent space.

� Dilution can be effective if the rate of smoke

leakage is small compared to either the total

volume of the safeguarded space or the rate

of purging air supplied to and removed from

the space.



Methods of Pressurization of

Stairwell

�To provide smoke-free

escape route in the event

of building fire

�To provide smoke-free

area for fire fighters.

Objectives


Methods of Pressurization of Stairwell


Methods of Pressurization of Stairwell


Pressure Sandwich


Pressure Sandwich


Testing of Smoke Control Systems

Initial Testing

�To assure that the system is operated as

designed

� Possible problems :

�fans operate backward

�no electric power is supplied to fans

�controls do not work properly . . . etc.


Testing of Smoke Control Systems

Regular Testing

� Measure pressure differences at

pressurization

� Measure air flow velocity from stairwell

through doors to various spaces


Computer Based Security Systems


Intrusion Detection System

• Some minimum requirements:

– Entrance to each office door

– Motion detection in each office

– Foyer motion detectors

– CCTV in each foyer, lobby, and parking area.


Access Control System

Areas requiring medium level

access security will be controlled by the

access card, keypad with

memorized pass-number & fingerprint

verification.


Television Systems


Card Reader BiometricsDoor Alarm

Live CameraFeeds

Card ReaderDatabase

Door AlarmDatabase

BiometricsDatabase

SmartCatchVision

Central Matrix Switch

ALERTS

RULES

Card Readersignal


Security Guard Patrol System

• Conduct scheduled fire and security patrols.

• Guards patrol all floors throughout day and night.

• Record guards movements with access reader.

• May find problems with communications due to steel buildings.

• Can use intercom system


Fire Control System

Fire Detection

&

Alarming

Automatic Fire

Fighting: Sprinklers


Fire Alarm: Survivability Requirements

The Code requires that all circuits necessary for the operation of the

notification appliances be protected until they enter the evacuation signaling zone

that they serve. Any of the following methods meet the survivability

requirements:

• A two-hour rated cable or cable system

• A two-hour rated enclosure

• Performance alternatives approved by the Authority Having Jurisdiction.


Emergency telephone stations are positioned at every floor throughout the

building to enable fire department personnel to communicate freely in their

fire fighting efforts.

The emergency phone system provides two-way communications throughout the

entire facility

Fire Alarm Fire Fighters

Telephone Systems


This is to enables occupants to safely escape the building in the event of a power

failure.

This must be equipped with back up batteries capable of powering exit and

emergency lights for more than an hour

In high rise buildings emergency lights should be connected to the building fire

alarm system.

Emergency Lights


Emergency Power

The building should have an emergency power generator.


Air Conditioning

Systems


Air-Conditioning System Alternatives

• All-Air Variable Air Volume (VAV)

Systems

�Alternative types of VAV boxes

�Low Temperature Air VAV Systems

• Air-Water Systems

• Underfloor Air Systems


Variable Air Volume Constant Air Volume


Underfloor Air Systems


Air Distribution Alternative Systems

Alternative 1

Central Fan Room

Alternative 2

Floor-by-Floor Fan Rooms with Chilled Water Units

Alternative 3

Floor-by-Floor Fan Rooms with Direct Expansion Units


Alternative 1—Central Fan Room

• Multiple AHU systems in one or more

room

• Supply air delivered into a common

discharge header from all of the supply

systems

• Vertical risers in two-hour fire-rated

shafts within the core of the building

• At each floor: horizontal duct taps with a

fire damper


Alternative 2—Floor-by-Floor Fan

Rooms with Chilled Water Units

A local floor fan room, located within building core

Chilled water for the cooling coil is provided by a central chilled water plant


Alternative 2—Floor-by-Floor Fan Rooms


POINTS OF COMPARISON OF ALTERNATIVE SCHEMES

• First Cost

• Construction Schedule Impact

• Owner Issues

• Equipment Considerations

• Architectural Issues


Central Heating and Cooling Plants

Design Factors

• Weight, space requirements, and impact on structural system.

• Effect on the construction schedule.

• Specific changes in mechanical room detailing and slab construction within which the equipment is located.

• Acoustical considerations.



• Ease & cost of operation and

maintenance

• Available energy sources.

• Life-cycle costs of each alternative

solution

• Space and cost considerations of a long

vertical flue from the fossil-fueled boiler




Central Plant

Locations


Acoustical Considerations

of Central Plant Locations

• Location of all equipment: allow achievement of desired acoustical levels in spaces above, below, or adjacent to central plants

• Solution will involve an understanding of characteristics of the sound generated by equipment and alternative paths


Acoustical Considerations

of Central Plant Locations

Sound paths

• Transmission of noise itself through floors,

ceilings, and walls of mechanical space

• Vibration and noise associated with

vibration that is transmitted by building

structure to occupied areas


Chilled Water Piping Arrangement:

Direct Water Pumps


Chilled Water Piping Arrangement:

Primary

&

Secondary Pumps


Chillers Location

Virtually at any floor

Example:

70-storey, 900 foot

Open type expansion


Chillers Location

Constrains

• Standard working pressure for chillers and heat

transfer equipment: 150 PSIG (1,000kPa).

• Additional cost for higher working pressure

(None proportional).


Pressure Reduction: Alternative A

• Pump at discharge side of chiller

• Primary pumps & no secondary for chiller circuit

• Zone H.E. with secondary pumps


Plate-and-frame H.E

The maximum head of each zone is 143 PSIG (986 kPa), which is below the threshold design pressure of 150 PSIG (1000kPa)


The Economics Of Temperature Differentials

• Small buildings– a 10°F or 12°F DT in the chiller

– a 10°F DT or 3 gpm per ton for the condenser.

• HRB: capital costs of the piping, valves, and fittings can be substantially reduced, with a possible penalty in refrigeration machine operating cost, by using larger DT with a lower flow of water


Conclusion

Higher DT in both the chiller and condenser is worthy of evaluation, as

there can be significant savings in cost of piping, fittings, and valves

The Economics Of Temperature Differentials


Fire Safety Problem

A high-rise building is one in which emergency evacuation is not practical and in which fires

must be fought internally because of height


Design of Life Safety Systems

• Architect

• Structure design engineer

• HVAC design engineer

• Electrical design engineer

• Fire fighting design

engineer


Components of Fire Management System

• Detection system

• Fire standpipe and automatic sprinkler systems

• Smoke management system

• Emergency electric power system

• Automatic elevator recall system

• Communication and alarm notification systems

• Central fire command center.


• In return air connection on each floor

• Downstream of filters in each supply system

• Ceiling of each elevator lobby

• Mechanical equipment rooms

• Transformer and telephone equipment rooms,

• Similar spaces unless room is protected by an automatic suppression system such as sprinklers.

Smoke Detectors Locations


Control Network



Internet BMS



Internet BMS


Definition of

Building Commissioning -1

Commissioning is a

quality assurance

process of

the installation of the

systems in a building.


Definition of

Building Commissioning -2

• It is a process for achieving,

verifying and documenting the

performance of each system to

meet the operational needs of the

building within the capabilities of

the documented design and

specified equipment capacities,

according to the owner’s

functional criteria.


Definition

of

Building

Commissioning -3

Successful

commissioning

includes the preparation

of manuals and training

of operation and

maintenance personnel


The definition refers to the building as a total

system, which includes the structural elements, building envelope, life safety features, security systems, elevators,

escalators, plumbing, electrical, controls, and the HVAC.

Definition of

Building Commissioning - 4


Advantages of Building

Commissioning

� Open channels of communication.

� Create a better understanding of design intent.

� Provide early assignment of performance responsibilities.

� Set performance goals such as energy, environment, and life cycle.



Commissioning

�Establish continuous monitoring of priorities and schedules.

�Improve operation and maintenanceprograms.

�Improve quality of operator personnel training.


Reduce callbacks

and assist in

dealing with

warranty claims.Enable owner to

recognize system

capabilities and

limitations


Commissioning


Commissioning Team

� Commissioning authority

� ( qualified professional company or agency that implements the overall commissioning process )

� Owner

� Design professionals
