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SEMI S14-0704 © SEMI 2000, 2004 13 R2-4.3 Smoke removal system intak e locations are dependent on the fabrication ar ea design. Design alternatives should be a ddressed with a com petent fire protection e ngineering desi…

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SEMI S14-0704 © SEMI 2000, 2004 12
RELATED INFORMATION 2
SMOKE MANAGEMENT IN CLEANROOMS
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.
R2-1 Introduction
R2-1.1 Semiconductor cleanrooms are operationally
sensitive to products of a fire. A fire will result in
smoke and corrosive particle contamination to the
cleanroom, process equipment, and work in process. A
properly designed, installed, and maintained smoke
detection and control system will not prevent
contamination, but will limit the spread and
concentration of the contaminant. The basis of the
smoke control system design should be aligned with the
organization’s risk management objectives.
R2-1.2 This Related Information deals with smoke
management systems for cleanrooms themselves, not
for equipment. Smoke removal from a cleanroom may
be performed by ventilation systems that are in place
for other purposes (e.g., process exhaust systems of
equipment) or by equipment designed and installed
specifically to remove smoke from the room. These
may both be parts of the protection for a cleanroom and
may differ in how they are activated.
R2-2 Actuation
R2-2.1 Automatic actuation of dedicated smoke control
systems is preferable; however, many facilities prefer
manual activation. If the system is manually activated,
the following should be done.
R2-2.1.1 The smoke detection system should be
monitored by qualified personnel 24 hours per day.
R2-2.1.2 Emergency response teams (ERT) or other
personnel authorized to actuate the manual smoke
control system should be capable of prompt
notification.
R2-2.1.3 Detailed smoke control emergency
procedures should be documented and practiced. These
procedures can include hazardous gas shutdowns and
shutdowns of appropriate air recirculation fans as well
as activating the smoke control exhaust fans.
R2-2.2 A secondary means of manual actuation of the
smoke/contaminant control system should be provided
in a clearly marked and accessible area outside the
cleanroom.
R2-3 Capacity
R2-3.1 The smoke control system capacity needed is
directly related to the design fire size which depends
upon the type, amount and arrangement of combustible
materials in the cleanroom. In order to achieve a
system that is economically feasible, the maximum
design fire size should be limited to the fire size at
sprinkler operation. For a typical cleanroom
configuration, the fire size at sprinkler operation is in
the range of 600 to 800 kilowatts.
R2-3.2 Smoke removal system capacity can be
designed based on an integrated system approach. The
total capacity can include the fume exhaust system
capacity and dedicated smoke removal system capacity.
R2-4 Design Considerations
R2-4.1 When the fume exhaust system is used for
smoke removal, the following design parameters should
be followed.
R2-4.1.1 The fume exhaust system ductwork should be
of non-combustible construction or should be
listed/approved for smoke removal and not incorporate
the use of fire dampers or interrupters.
R2-4.1.2 It should be confirmed that sufficient fume
exhaust system intake points exist throughout the clean
room. If not, additional intake points should be
provided and incorporate the use of normally closed
dampers. These dampers should be opened either
automatically by activation of the smoke detection
system or by manual means.
R2-4.1.3 When the fume exhaust system is used for
smoke removal, it can incorporate the use of variable
speed fan(s). During the smoke removal mode, fire
dampers on supplemental intake points will open and
the fan speed will be increased. The design capture
velocity at the tool(s) could be affected, and this should
be reviewed. Necessary balancing changes should be
made to ensure the design capture velocity is
maintained.
R2-4.2 The ventilation system make-up air fans should
be sized such that under full smoke and process
exhaust, the fabrication area maintains a positive
pressure relative the adjacent areas.
SEMI S14-0704 © SEMI 2000, 2004 13
R2-4.3 Smoke removal system intake locations are
dependent on the fabrication area design. Design
alternatives should be addressed with a competent fire
protection engineering design firm. For example, for
open manufacturing areas, smoke removal system
intake sequencing should be designed such that
individual zones can be activated to prevent
contaminant migration to adjacent clean areas of the
fab. From a smoke removal perspective, ducted returns
are a better option than open attic plenum
configurations.
R2-5 Testing
R2-5.1 The smoke/contaminant control system should
have a functional test done annually of all detection and
control systems including system dampers and fans.
The system should be designed so that operational and
functional testing can be done without interruption to
the normal clean room air handling.
R2-5.2 The smoke/contaminant control system for new
semiconductor facilities should be fully tested during
mechanical system tests done near the end of the
construction process. Testing should consist of a
complete functional test of detection and control
systems, plus activation of smoke/contaminant removal
fan and damper systems. The performance of the
smoke/contaminant removal system should be verified
using either sulfur hexafluoride (SF
6
) or another tracer
gas method.
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
2
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