Download Fume Hood Requirements

FUME HOOD
REQUIREMENTS
Building Division
City of Palo Alto (CPA)
Building Inspection
285 Hamilton Ave.
Inspection Request: 650 329-2496
Revision Date: 2011
General Requirements/Checklist for:
Commercial
Codes Enforced:
2010 CBC, CPC, CMC, NFPA, CFC
The information provided in this document is general and intended as a guide only. Each project is unique and additional
requirements may be enforced as deemed appropriate.
Plans shall be submitted to the city plan check to verify requirements mandated by CBC,
CEC, CPC, CMC, NFPA standards, CFC, and City of Palo Alto Fire Prevention
Bureau/Building Division Standard No.1 (see attachment).
 Inspections shall be required to verify equipment is properly secured to meet
minimum seismic connection requirements.
 All equipment used inside the fume hood shall be tested and certified by a
recognized testing agency.
 Hood construction shall be non-combustible in accordance with CBC standard 2-1
and City of Palo Alto Standard No.1 (see attachment).
 Electrical receptacles shall not be located within the hood enclosure.
 Electrical apparatus and appliances located within the hood interior are regulated
by City of Palo Alto Standard No.1 and current California Electrical Code
ART.500.
 Lighting shall be separated from the hood interior by a vapor tight barrier of
safety glass or otherwise approved by the Building Division.
 Inspection required to verify Exhaust Requirements of fume hood to CMC
Requirements, specifically, Section 505, 506 and 610.
 All ducting requirements shall adhere to City of Palo Alto Standard No. 1 and
CMC.
 All duct material shall be metal and constructed in accordance with CMC Section
505, 506 and 610.
 Minimum air velocities are specified by CMC Section 505.2.
 CMC Section 502.1 defines product conveying duct classification.
 Ducts conveying explosive or flammable vapors, fumes or dust shall extend
directly to the exterior of the building without entering other spaces.
 Termination of exhaust shall conform to CMC Section 506.9.
 Make up air shall be provided to replenish air exhausted by the fume hood
ventilation system make-up intakes shall be located to avoid recirculation of
contaminated air.
 An airflow interlock shall be required to meet City of Palo Alto Standard No.1
unless fume hood ventilations is connected to standby or emergency power.
Requirements shall comply with City of Palo Alto Standard No. 1 UFC, NFPA Standards
and will require fire department review and approval.
Inspection of all aspects of fume hood installation and operation will be required by
Building Department, Fire Department and Hazmat.
Building/Fire Standard No. 1
Flammable Liquids in Fume Hoods
FLAMMABLE LIQUIDS IN FUME HOODS
Current California Fire Code, Section 8001.4.4 requires equipment utilized for
dispensing, use or handling of hazardous materials shall be approved, listed, or designed
in accordance with approved standards for the intended use. Listed fume hoods are
presently unavailable due to the impracticality of testing myriad combinations of liquids
in conjunction with fume hood use.
The intent of this document is to establish a set of standard conditions of approval for
typical vessels used in fume hoods and the fume hoods themselves for research processes
and similar activities involving stirring, mixing and/or heating of flammable or
combustible liquids.
Activities where use of flammable liquids is limited to incidental activities such as
cleaning using small quantities (example: squirt bottle) will be exempt from the
following requirements. For purposes of this standard, workstations within Group H,
Division 6 Occupancies constructed and maintained in accordance with Article 51 of the
Uniform Fire Code will not be considered fume hoods.
NEW CONSTRUCTION
New installations of fume hoods where flammable liquids are used shall be required to
have all of the following”
1.
Sprinklered Buildings - A sprinkler heard shall be provided within the fume hood
to cover the workbench. The sprinkler head shall be listed corrosion resistant or
adequately protected by an approved method such as bee’s wax coating.
Non-Sprinklered Buildings – An automatic fire-extinguishing system shall be
provided if the Fire Department determines that the manner of use in the hood
constitutes an extraordinary hazard.
2.
Lighting shall be separated from the hood interior by a vapor-tight barrier of
Safety glass or otherwise approved by the Building Division.
3.
Hood construction shall be noncombustible in accordance with UBC Standard 21 surfacing materials not over 1/8 inches thick, with a flame-spread rating of 25
or less are allowed in accordance with NFPA 45.
4.
Ducting shall be metallic and constructed in accordance with the current
California Uniform Mechanical Code Sections 505, 506 and 609.
5. Sprinklers shall be installed within ducts having a cross-sectional dimension
exceeding 10 inches, unless calculations are submitted to the Fire Prevention
Bureau demonstrating that a “reasonable worst case” spill scenario will not
result in vapor concentration over 10% of the Lower Explosive (Flammable)
Limit. Sprinklers shall be installed at 12-foot intervals in horizontal ducts
and at changes in direction. In vertical runs, sprinklers shall be installed at
the top and at alternate floor levels.
6. An airflow interlock shall be provided to shut off electricity and flow of
flammable or combustible materials to equipment inside the hood. The
interlock shall activate at >50% loss of measured airflow. NOTE: Interlock
shall not be required where fume hood ventilation is connected to standby or
emergency power.
7. Electrical receptacles shall not be located within the hood interior unless
otherwise approved by the Building Division.
8. Electrical apparatus and appliances located within hood interior are not
normally required to be rated for hazardous locations. When atypical
operations involving spraying or other potentially high-hazard activities are
to be conducted, the Hazardous Materials Bureau and the Building Division
shall review the intended use of the fume hood and determine the
classification of the interior and required ratings for electrical equipment in
accordance with current California Electrical Code, Article 500.
CONTINUED USE OF EXISTING FUME HOODS
Where such activities are conducted in fume hoods previously legally installed (i.e. with
mechanical and electrical permits), continued use of existing fume hoods not in
compliance with the above guidelines will be allowed unless the Fire Marshal determines
that an imminent hazard exists.
Building Official
Fire Marshal