semi合集-English.pdf - 第6788页

SEMI S2-0703a E © SEMI 1991, 2004 17 NOTE 47: Some regional codes (e.g ., Uniform Fire Code) may require construction with noncombustible m aterials. 14.4.1.1 The flowcha rt in Appen dix 6 may be used for the selection o…

SEMI S2-0703a

 the main circuit breaker is opened.

EXCEPTION: Upon EMO activation, the UPS may

supply power to the EMO circuit, safety related

devices, and data/alarm logging computer systems as

described in the exception clauses of Section 12.2.

13.5.3 The UPS may be physically located within the

footprint of the equipment provided that the UPS is

within its own enclosure and is clearly identified.

13.5.4 The UPS should be certified by an accredited

testing laboratory and be suitable for its intended

environment (e.g., damp location, exposure to

corrosives).

13.5.5 The UPS wiring should be identified as “UPS

Supply Output” or equivalent at each termination point

where the UPS wiring can be disconnected.

13.6 Electrical Safety Tests

13.6.1 Equipment connected to the facility branch

circuit with a cord and plug should not exhibit surface

leakage current greater than 3.5 milliampere (mA) as

determined by testing completed in accordance with

“Leakage Current Test for Plug-and-Cord Equipment”

in SEMI S9.

EXCEPTION: Equipment with leakage current

exceeding 3.5 mA is acceptable if documentation is

provided to substantiate that the equipment is fully

compliant with an applicable product safety standard

that explicitly permits a higher leakage current.

13.6.2 Equipment grounding circuits should have a

measured resistance of one-tenth (0.1) ohm or less as

determined by testing in accordance with SEMI S9.

13.7 Equipment in which flammable liquids or gases

are used should be assessed to determine if additional

precautions (e.g., purging) in the electrical design are

necessary.

NOTE 44: NFPA 497 and EN 1127-1 provide methods for

making this assessment.

14 Fire Protection

14.1 Overview — This section applies to fire hazards

that are internal to the equipment.

14.1.1 This section provides minimum safety

considerations for fire protection designs and controls

on the equipment.

14.1.2 This section also provides minimum

considerations for fire detection and suppression

systems when provided with the equipment.

NOTE 45: Detailed guidance on fire risk assessment and

mitigation for semiconductor manufacturing equipment is

provided in SEMI S14.

14.2 Risk Assessment

14.2.1 A documented risk assessment should be

performed or accepted by a party qualified to determine

and evaluate fire hazards and the potential need for

controls. The risk assessment should consider normal

operations and reasonably foreseeable single-point

failures within the equipment. It should not consider

exposure to fire or external ignition sources not within

the specified use environment.

NOTE 46: This risk assessment can be combined with the

overall hazard analysis performed for this guideline, provided

the risk assessor has the required professional expertise to

perform risk assessments for fire hazards. SEMI S7 describes

qualifications for such an assessor.

14.2.2 If an accurate risk assessment depends on the

user’s adherence to specified procedures or conditions

of use, the supplier should describe such procedures or

conditions and state their importance.

14.2.3 SEMI S14 should be used to assess and report

risks to property and the environment.

14.3 Reporting

14.3.1 A summary report should be provided to the

user. The summary should include the following

characterizations, per SEMI S10, for each residual fire

hazard identified:

 the assigned Severity;

 the assigned Likelihood; and

 the resulting Risk Category.

14.3.2 Optional fire risk reduction features should be

described in the pre-purchase information provided to

the user.

14.3.3 The scope and effectiveness of the means of fire

risk reduction should also be identified and reported,

including the expected risk reduction (as described in

Section 14.3.1).

14.3.4 If, due to fire hazards within the equipment,

thermal or non-thermal (e.g., smoke) damage is

possible outside of the equipment, then this possibility

should be reported to the user. This report should

include a qualitative description of the foreseen

scenario.

14.4 Fire Risk Reduction

14.4.1 Materials of Construction — Equipment should

be constructed of noncombustible materials wherever

reasonable. If process chemicals do not permit the use

of noncombustible construction, then the equipment

should be constructed of materials, suitable for the uses

and compatible with the process chemicals used, that

contribute least to the fire risk.

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