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SEMI S2-0703a E © SEMI 1991, 2004 18  allowing the completion o f processing of substrates in the equipment;  prevention of pro cessing of additional substrates until the troub le or supervisory condition is cleared; a…

SEMI S2-0703a

NOTE 47: Some regional codes (e.g., Uniform Fire Code)

may require construction with noncombustible materials.

14.4.1.1 The flowchart in Appendix 6 may be used for

the selection of materials of construction for equipment.

14.4.1.2 Any portion of equipment that falls within the

scope of SEMI F14 (Guide for the Design of Gas

Source Equipment Enclosures) should be designed in

accordance with that guide.

14.4.2 Elimination of Process Chemical Hazards —

The option of substituting non-flammable process

chemicals for flammable process chemicals should be

considered.

14.4.3 Engineering Controls

14.4.3.1 Fire risks resulting from process chemicals

may be reduced using engineering controls (e.g.,

preventing improper chemical mixing, preventing

temperatures from reaching the flash point).

14.4.3.2 Fire risks resulting from materials of

construction may be reduced using engineering controls

(e.g., non-combustible barriers that separate

combustible materials of construction from ignition

sources, installing a fire suppression system that

extinguishes ignited materials).

14.4.3.3 Equipment power and chemical sources that

present unacceptable fire risks should be interlocked

with the fire detection and suppression systems to

prevent start-up of the equipment or delivery of

chemicals when the fire detection or suppression is

inactive.

NOTE 48: Some jurisdictions require interlocking.

NOTE 49: Refer to Section 6.5 for criteria for acceptability.

14.4.3.4 Shutdown or failure of a fire detection or

suppression system need not interrupt the processing of

product within the equipment by immediately shutting

down the equipment, but should prevent additional

processing until the fire detection or suppression is

restored. Software or hardware may be used for this

function.

14.4.3.5 Controlling smoke by exhausting it (using the

supplier-specified equipment exhaust) from the

cleanroom may be used to reduce fire risks from the

generation of products of combustion. When used, this

reduction method should be combined with detection or

suppression when flames can be propagated.

NOTE 50: Controlling smoke may be sufficient when smoke

is the only consequence (e.g., smoldering components that

generate smoke).

NOTE 51: For controlling smoke to be effective, the smoke

must be removed not only from the equipment, but also from

the cleanroom. This is typically accomplished by using ducted

exhaust.

NOTE 52: The use of exhaust to remove smoke may be

subject to regulations, such as building and fire codes.

NOTE 53: The use of exhaust to remove smoke may create

hazards within the exhaust system. Therefore, a description of

the expected discharge (i.e., anticipated air flow rate,

temperature, and rate of smoke generation) into the exhaust

system may be important information for installation of

equipment.

14.4.4 Fire Detection — The following criteria apply

to any fire detection system determined to be

appropriate for fire protection by the fire risk

assessment:

NOTE 54: Heat detectors, smoke sensing devices, and other

devices used solely for monitoring equipment status may not

need to meet these requirements. Some local jurisdictions,

however, may require that all smoke detectors be connected to

building systems and be compliant with all applicable fire

alarm codes.

14.4.4.1 The fire detection system, which includes

detectors, alarms and their associated controls, should

be certified by an accredited testing laboratory and

suitable for the application and for the environment in

which it is to be used.

NOTE 55: Such certifications typically require that the

components of fire detection systems are readily identifiable

and distinguishable from other components in the equipment.

14.4.4.2 The fire detection, alarm and control system

should be installed in accordance with the requirements

of the certification in Section 14.4.4.1, and in

accordance with requirements of the appropriate

international or national codes or standards (e.g., NFPA

72).

14.4.4.3 The fire detection system should be capable of

interfacing with the facility’s alarm system. It may be

preferable for the equipment supplier to specify the

location and performance of detectors, but not provide

them, so that the user may better integrate the detection

in the equipment with that in the facility. This

alternative should be negotiated explicitly with the user.

14.4.4.4 The fire detection system should activate

alarms audibly and visually at the equipment.

14.4.4.5 Manual activation capability for the fire

detection system should be considered, for the purpose

of providing notification to a constantly attended

location.

14.4.4.6 Activation of trouble or supervisory

conditions should result in all of the following:

 notification of the operator;

SEMI S2-0703a

 allowing the completion of processing of substrates

in the equipment;

 prevention of processing of additional substrates

until the trouble or supervisory condition is

cleared; and

 providing, through an external interface, a signal to

the facility monitoring system or a constantly

attended location.

NOTE 56: Some local jurisdictions require that such alarms

signal the building/facility fire alarm systems.

14.4.4.7 The fire detection system should be capable of

operating at all times, including when the equipment is

inoperable (e.g., equipment controller problems) or in

maintenance modes (e.g., some or all of the

equipment’s hazardous energies are isolated (“locked

out”). For the purpose of this section, “inoperable”

includes the equipment states after an EMO is activated

and after the equipment has had its hazardous energies

isolated (i.e., has been “locked out”). Therefore, the

detection system should not require hazardous voltages

(e.g., line alternating current) to operate anything other

than the equipment within the detection system’s

control enclosure. Sensors and other devices outside

the detection system’s control enclosure should not

require hazardous voltage.

EXCEPTION: Operability is not required during

maintenance of the fire detection system.

14.4.4.7.1 Power at a hazardous voltage may be

supplied to the detection system controller enclosure

after the equipment EMO is activated or after the

equipment has had its hazardous energies isolated only

if the wiring providing the hazardous voltage is

separated from other wiring and is suitably labeled.

14.4.4.7.2 If the hazardous voltage supply to the

detection system controller is not disconnected by the

energy isolation method that removes the other

hazardous voltages from the equipment, there must also

be separate hazardous energy isolation capability for

the hazardous voltage supplies to the detection system

controller enclosure.

14.4.4.8 A battery or other regulatory agency

acceptable emergency power alternative, capable of

sustaining the detection system for 24 hours, should be

provided.

NOTE 57: Back-up power must be provided in accordance

with local regulations. The requirements for back-up power

vary among jurisdictions.

14.4.4.9 The fire detection system should remain active

following EMO activation.

14.4.4.10 There may be cases where the internal power

supply for a detection system cannot supply power for

the full length of extended maintenance procedures

(i.e., procedures longer than the expected duration of

the back-up power supply). In such cases, the supplier

should provide written procedures for either removing

the fire hazard or safely supplying power to the fire

detection system.

14.4.4.11 Activation of the fire detection system

should shut down the equipment within the shortest

time period that allows for safe equipment shutdown.

This includes shutdown of any fire-related hazard

source that could create additional fire risks for the

affected module or component.

NOTE 58: See Sections 14.4.3.3 and 14.4.3.4 for related

provisions.

EXCEPTION 1: A non-recycling, deadman abort

switch is acceptable on detection systems that are used

for equipment shutdown, but not on those used for

activation of a suppression system.

EXCEPTION 2: Activation of the fire detection system

should not remove power from fire and safety systems.

14.4.4.12 The equipment design and configuration

should not prevent licensed parties from certifying the

design and installation of fire detection systems.

NOTE 59: This is not meant to suggest installation by

licensed parties; however, some jurisdictions require fire

detection and suppression system installers to be licensed as

specified by the jurisdiction.

14.4.5 Fire Suppression — The following criteria

apply to any fire suppression system determined to be

appropriate by the fire risk assessment.

NOTE 60: As a fire detection system is generally required to

provide the initiating sequence for the suppression system, it

is the intention of this guideline that this be the same fire

detection system described in Section 14.4.4.

14.4.5.1 The fire suppression system, which includes

nozzles, actuators, and their associated controls, should

be certified by an accredited testing laboratory and

suitable for the application and for the environment in

which it to be used.

NOTE 61: Such certifications typically require that the

components of fire suppression systems are readily

identifiable and distinguishable from other components in the

equipment. This includes adequate labeling of piping.

14.4.5.2 The fire suppression agent should be accepted

for the application by an accredited testing laboratory.

The suppression agent selection process should include

an evaluation of the amount and storage location of the

suppression agent and of potential damage to a

cleanroom and the environment. The least damaging

effective agent should be selected. If more than one

SEMI S2-0703a

agent is effective, the options should be specified to the

user so that the user may specify which agent should be

provided with the equipment. The supplier should also

specify if the user may provide the agent.

14.4.5.3 The fire suppression agent and delivery

system should be designed and installed in accordance

with the appropriate international or national standard

(e.g., NFPA 12, NFPA 13, NFPA 2001). It may be

preferable for the equipment supplier to specify the

location and performance of suppression system

components, but not provide them, so that the user may

better integrate the suppression in the equipment with

that in the facility. This alternative should be negotiated

explicitly with the user.

14.4.5.4 The assessment of the equipment to SEMI S2

should include the risks associated with the suppression

systems.

NOTE 62: This includes risks (e.g., chemical exposure,

noise, and asphyxiation) introduced by the incorporation of

the suppression system.

14.4.5.5 Activation of the fire suppression system

should alarm audibly and visually at the equipment.

This may be done by the same system that initiates

activation.

14.4.5.6 If the discharge is likely to present a risk to

personnel, the alarm should provide adequate time to

allow personnel to avoid the hazard of the agent

discharge.

14.4.5.6.1 If there is a confined space in the equipment,

the asphyxiation hazard posed by the suppression

system should be assessed.

14.4.5.7 The fire suppression system should be capable

of operating at all times, including when equipment is

inoperable and during equipment maintenance.

NOTE 63: For the purpose of this section, “inoperable”

includes the equipment state after the EMO is activated.

EXCEPTION: Most suppression systems contain

sources of hazardous energy. These sources should be

capable of being isolated (i.e., “locked out”) to protect

personnel.

14.4.5.8 The fire suppression system should remain

active following EMO activation.

14.4.5.9 There may be cases where the internal power

supply for a suppression system cannot supply power

for the full length of extended maintenance procedures

(i.e., procedures longer than the expected duration of

the back-up power supply). In such cases, the supplier

should provide written procedures for either removing

the fire hazard or safely supplying power to the fire

suppression system.

14.4.5.10 Allowances can be made to provide for the

deactivation of an automatic discharge of the

suppression system when in the maintenance mode.

Such deactivation switches should be supervised (i.e., if

the suppression system is deactivated, there should be

an indication to the user and the resumption of

production in the equipment should be prevented.)

NOTE 64: Hazardous energies associated with the fire

suppression system may be isolated (i.e., “locked out”) using

an energy isolation procedure (see Section 17) during

equipment maintenance.

NOTE 65: The permissibility of deactivation of suppression

systems varies among jurisdictions.

14.4.5.11 A back-up power supply, capable of

sustaining the suppression system for 24 hours, should

be included where the suppression system requires

independent power from the detection system used to

activate the suppression.

NOTE 66: The requirements for back-up power vary among

jurisdictions.

14.4.5.12 The fire suppression system should be

capable of interfacing with the facility’s alarm system.

This may be done via the fire detection system.

14.4.5.13 Activation of the fire suppression system

should shut down the equipment within the shortest

time period that allows for safe equipment shutdown.

NOTE 67: See Sections 14.4.3.3 and 14.4.3.4 for related

provisions.

EXCEPTION: Activation of the fire suppression system

should not remove power from fire and safety systems.

14.4.5.14 The fire suppression system should be

capable of manual activation, which should shut down

the equipment and activate an alarm signal locally and

at a constantly attended location.

14.4.5.15 The fire suppression system should be tested

on a representative sample of the equipment. The test

procedure should include a suppression agent discharge

test, unless precluded for health or environmental

reasons. This test may be performed at the equipment

supplier’s or other similar facility, but should be

performed under conditions that adequately duplicate

any factors (e.g., equipment exhaust) that may reduce

the effectiveness of the suppression. This representative

sample need not be fully operational, but should

duplicate those factors (e.g., exhaust, air flow) that

could negatively affect the performance of the system.

14.4.5.16 Procedures for controlling access to the

suppression agent source (e.g., protecting agent

cylinders from disconnection by unauthorized

personnel) should be provided.