12-Preiss RBI

www.tuv.at © TÜV AUSTRIA SERVICES GMBH / 2010

Risk Based

Approaches in

Conformity

Assessment

Process Safety,

Pressure Equipment,

Machinery & Inspection

Dr. Reinhard Preiss

www.tuv.at © TÜV AUSTRIA SERVICES GMBH / Dr. R. Preiss / 2010 page 2

Overview

1. Process Safety – risk analysis & functional

safety

2. Pressure Equipment – safety concept of

assemblies

3. Machinery – risk analysis & functional safety

4. Risk Based Inspection of pressure equipment

Industrial fields of application of risk

based approaches to achieve

technical safety

APPLICATION

To show compliance with the

requirements of Directives and Codes /

Standards

CONFORMITY ASSESSMENT


Process Safety

IEC 61511 / ISA-84.00.01

Safety instrumented systems for the process industry sector

Clause 8: Hazard and Risk Assessment

The objectives of the requirements of this clause are:

> to determine the hazards and hazardous events of the process and

associated equipment;

> to determine the process risks associated with the hazardous event;

> to determine any requirements for

risk reduction;

> to determine the safety functions

required to achieve the necessary

risk reduction;


Process Safety

IEC 61511 / ISA-84.00.01

Informal annexes for possible determination of required risk

reduction by safety instrumented functions (SIL), e.g.


Process Safety

IEC 61511 / ISA-84.00.01

but no indication of safety target levels in general, e.g.

“..the plant internal safety target level for release of material to the

environment of 10-4 per year is not met…”

responsibility of the user


Pressure Equipment

Pressure Equipment Directive 97/23/EC

Assembly

Several pieces of pressure equipment assembled by a manufacturer to

constitute an integrated and functional whole.

Annex I, ESR

Where, under reasonably foreseeable conditions,

the allowable limits could be exceeded, the

pressure equipment must be fitted with suitable

protective devices, unless the equipment is

intended to be protected by other protective

devices within an assembly.


Pressure Equipment

Pressure Equipment Directive 97/23/EC

Thus, examination of the safety of an assembly, i.e.

conformity assessment with regard to the ESR of the

Directive, requires consideration of deviations from

the intended operation.

But, there are nor further statements on what is

“reasonably foreseeable” and on required risk

reduction (no safeguard is perfect) in the Directive.

in practice, a risk based approach, e.g. as

given in IEC 61511 is used.


Machinery

Machinery Directive 2006/42/EC

> The manufacturer of machinery must ensure that a risk assessment is

carried out in order to determine the health and safety requirements which

apply to the machinery. The machinery must then be designed and

constructed taking into account the results of the risk assessment.

> It is required to estimate the risks, taking into account the severity of the

possible injury or damage to health and the probability of its occurrence.


Machinery

EN ISO 14121-1: Safety of machinery - Risk assessment - Part 1:

Principles

In practice:

Risk reduction measures according to standards (harmonized product safety

standards), or according to state-of-the-art, or according to company

internal requirements.


Risk Bases Inspection

RBI Principle:

>Adjust inspection periods and inspection methodology according to

probability of failure and consequence of failure of the equipment,

i.e. adjustment according to the risk.

>In some countries inspection periods are

given due to legal requirements but

exclusions based on RBI are possible, in

others RBI can be used regularly.

> Inspection bodies can play an important

role in that context.



>Systematic evaluation of damage mechanisms and estimation of

the probability of failure (PoF)

>Determination of possible consequences (harm to people,

environment and asset losses) in case of equipment failure (CoF)

>Equipment is ranked in a risk matrix

>Based on the ranking inspection activities

are determined

Consequence

Pro

ba

bilit

y

A B C D E

1

2

3

4

5

Very High

High

Medium

Low

Very Low

R I S K



Codes & Standards

>RIMAP application workbooks according to the European R&D

Project GIRD-CT-2001-03008:

>CEN Workshop Agreement CWA 15740:2008

>API RP 580, 1st Edition, 2002-05

>API RP 581, 2nd Edition, 2008-09

>HSE Safety implications of European risk based inspection and

maintenance methodology; Research report 304/2005

An EN/ISO standard on RBI principles and application

is of high importance!

Documents

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