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SEMI S14-0704 © SEMI 2000, 2004 15 the field review sh ould concentrat e on ensuring t hat components are located so th at they can see the hazard without obstruct ion, including cl ear vision panels, which may pre vent …

SEMI S14-0704 © SEMI 2000, 2004 14

RELATED INFORMATION 3

ADDITIONAL CONSIDERATIONS FOR FIRE SUPPRESSION SYSTEMS

NOTICE: This related information is not an official part of SEMI S14 and was derived from the work of a member

of the Fire Protection Task Force of the North American Environmental, Health, and Safety Committee. This

related information was approved for publication by 2/3 committee vote on July 17, 2003.

R3-1 Introduction

R3-1.1 Preventing discharges from occurring

accidentally and ensuring that systems are able to fulfill

their intended function requires attention to detail from

the specification of the system, through design,

installation and commissioning and then through on-

going maintenance.

R3-1.2 The following information is intended to assist

stakeholders involved in the process of designing,

installing, and maintaining fire protection of

semiconductor manufacturing equipment. Further

information can be found in the appropriate fire

protection codes and standards applicable to the type of

fire protection system and in related documents.

NOTE R3-1: The term “fire suppression” is limited to

extinguishing fire, once it has begun. The term “fire

protection” incorporates fire suppression and other means of

mitigating the risk of fires, including fire detection and

materials selection.

R3-1.3 The use of contractors with previous experience

in the design and installation of fire protection of

cleanrooms and semiconductor manufacturing

equipment is desirable.

R3-1.4 Independent third party review of fire

protection designs and installations by a fire protection

engineer with relevant experience can also help to

ensure that systems are correctly designed and installed.

NOTE R3-2: The material in this Related Information is

presented as additional guidance in designing, installing, and

maintaining fire protection systems in semiconductor

manufacturing equipment. Although this information is

believed to be useful in optimizing such systems, the material

in this Related Information does not comprise additional

criteria for determining conformance to the provisions of

SEMI S2 or SEMI S14.

R3-2 Design Review

R3-2.1 Ensure that system proposed uses approved or

listed components and that they are used within their

listing or approval, e.g., FM Approved wet bench fire

suppression systems should be used for open faced wet

bench whereas an enclosed tool can use a system

comprising of FM approved & compatible components.

R3-2.2 Detection needs to be selected to suit the

working environment and the type of fire/smoke that is

anticipated. For example, optical detectors need to

have been tested and approved/listed for use with

specific flammable liquids or gases. Flames and smoke

from burning materials have varying physical

characteristics which mean that some detection devices

will not always react promptly.

R3-2.3 The location of detection devices in relation to

hazards needs to be carefully considered. A detector

that is located too close to a heat source may activate

when it sees normal process conditions rather than fire

conditions.

R3-2.4 Some optical detectors may also be susceptible

to accidental activation if they are exposed to welding

flashes. Care in detector selection can avoid this, but

implementing strict cutting and welding working

practices and permissions can also play an important

part.

R3-3 Installation Review

R3-3.1 Once completed by the fire protection installer,

the fire protection installation should be inspected and

reviewed by a competent and experienced fire

protection engineer. This review will:

R3-3.1.1 Verify installation against previously working

drawings.

R3-3.1.2 Ensure that specified equipment has been

installed as indicated on the working drawings and in

line with equipment approvals and listings.

R3-3.2 Distribution pipework networks should be

complete (including all connections), properly

supported using listed and approved equipment.

Frequent failures of piped systems, including CO

systems, occur due to incorrectly connected pipes or

where fittings have not been made or sufficiently

tightened.

R3-3.3 Supports for pipework should be able to

withstand the expected forces that will be experienced

during discharge of the suppression system. This is

important to protect personnel and property from

moving pipes in high-pressure systems using agents

such as carbon dioxide.

R3-3.4 Detection systems should have components

installed as per reviewed drawings, however it is not

always possible during desktop drawing review to

identify that detectors are correctly sited. As a result

SEMI S14-0704 © SEMI 2000, 2004 15

the field review should concentrate on ensuring that

components are located so that they can see the hazard

without obstruction, including clear vision panels,

which may prevent detector from “seeing” the flame.

R3-3.5 Similarly detectors need to be sited so that they

will not experience normal process temperatures,

radiation or be exposed to chemical, liquid or particles

that could result in an accidental activation.

R3-3.6 Where linear heat detection cable is used it

should be located where it will not be exposed to levels

of ambient or process related heat that could trigger an

alarm signal. In addition the cable should be securely

attached to prevent it dislodging and coming into

contact with hot surfaces.

R3-3.7 Nozzle locations in many suppression systems

can be critical to ensuring functionality, reliability and

safety. For example, CO

nozzles incorrectly

positioned can result in chemical splashing or

dislodging product or quartzware. If nozzles are

exposed to chemical action including corrosive

chemicals, it is important that the materials are resistant

to the chemical

R3-3.8 Where automatic sprinkler heads are used, the

fusible link should be adequately protected from

chemical and mechanical attack.

R3-4 Commissioning Tests

R3-4.1 All installations should undergo a thorough

commissioning and acceptance test conducted by the

installer and witnessed by the owner or owner’s

representative.

R3-4.2 Functional Tests are essential, but not sufficient

to ensure that system will operate as in tended. The

types of problems that can be picked up by functional

testing are:

R3-4.2.1 Inability of detection system to detect as

intended,

R3-4.2.2 Inability of control system to receive signal

from individual detectors, and

R3-4.2.3 Inability of alarm panel to initiate system

discharge or send alarm signals to connected devices

and safety systems, e.g.,

• local or remote alarm panels,

• sounders & warning devices, and

• interlocks to equipment shutdown and safety

systems, EMO.

R3-4.3 Discharge Testing is the only way that we can

ensure that that a system will fulfill its intended

function. The types of problems that can be picked up

by discharge testing are:

R3-4.3.1 Lack of extinguishing agent

R3-4.3.2 Inability to transfer agent from supply to

nozzles due to:

• Blockages arising from incorrect equipment,

• Incomplete piping, loose fittings & supports, and

• Installation, design problems (e.g,. icing up of CO

pipes or nozzles).

R3-4.4 In many cases discharge testing within the

cleanroom environment is not considered acceptable or

practical. Accordingly, alternatives such as type testing

can prove that the design will provide the necessary

protection, but may need to be supplemented by a more

rigorous commissioning test of the final systems. Type

testing would involve the installation and discharge

testing of a system on a tool during manufacture or on a

mock up of the tool. The aim would be to prove that

distribution pipework and nozzles have been correctly

designed and that the concentration of agents and

distribution patterns from nozzles is acceptable. This

would be supplemented by additional tests on each

installation, including pressure tests of pipework and

“puff” tests to verify pipework integrity.

R3-5 Burn In

R3-5.1 In order to avoid unnecessary discharges, a

period of burn-in for the detection system is advisable.

This involves the detection system operating, enabling

detection of fires and initiation of alarms, but the

detection is not interlocked to shut down the process

equipment or initiate a discharge.

R3-5.2 A period of days or weeks may be appropriate

depending on the effect of an accidental activation of

the system in terms of interruption to processing,

damage to product or contamination of the

environment.

R3-6 Maintenance & Servicing

R3-6.1 Once systems are installed and commissioned it

is important that the routine inspection and maintenance

procedures recommended by manufacturers and those

required by codes and standards, are adequately

implemented.

R3-6.2 The inspection frequencies may need to be

modified if the ambient conditions can adversely affect

the protection systems. For example sprinkler heads

protecting corrosive fume exhaust ducts may need to be

inspected weekly or monthly until the appropriate

frequency for that particular system can be determined.

R3-6.3 Annual and semi-annual maintenance should be

carried out by competent personnel with adequate

training for the tasks in hand.