PLUMBING DESIGN by the NUMBERS

BY JAMES STENQVIST, CPD, LEED AP

Foodservice Gas
Appliance Safety
Cleanliness in a commercial kitchen is an
important issue that affects the health andsafety of the public consuming the foodbeing cooked and the workers preparing it
as well. To properly clean equipment, appliance mobility is required to ease movement, servicing, and positioning; thus,equipment with permanent casters in lieu
of fixed legs has become a standard practicein most kitchens. The casters have brakes toprevent accidental movement while cooking, and restraint cables are installed tolimit the amount of appliance movement
to prevent stress and damage to the gas
connector. Quick-disconnect couplings areused to rapidly disconnect and reconnect
connectors.

GAS CONNECTORS

allow a more hygienic environment by providing easy access around the equipment.
Their use increases efficiency and reduces
operating costs, allows appliances to be
set closer to the wall, and provides ease ofmobility for cleaning and maintenance.
They also meet updated code requirements,
including ANSI Z21.69/CSA 6.16: Connectors
for Movable Gas Appliances and CAN/CSA
B149.1: Natural Gas and Propane Installation Codes.
Rigid or hard-piped connections are madeto withstand physical damage; however,they are not practical for movement, andthis immobility increases the chance of fire
due to the buildup of oil, grease, and otherflammable materials. Equipment with hardpiped connections is difficult to clean andmaintain on a regular basis, which presents
the potential for food contamination. Also,
hard-piped connections do not comply with
NSF certification.

Codes and product standards have been
updated to include commercial-grade flexible gas connectors for all gas appliances
in a commercial foodservice kitchen. Theconnector is often a forgotten specification
item that goes unnoticed
until cited by the code official
at the final inspection andGAS PIPING EXPOSED ALONG BACK WALL BEHIND KITCHEN EQUIPMENT.
startup of the kitchen. If thedesigner or the foodservice
SHUTOFF VALVE - TYPICAL.
consultant doesn’t specify theDRIP LEG - TYPICAL.
connector, a residential appliance connector or a fixed,
SWIVEL 360° ROTATION FITTING.
hard-piped installation may
GAS PRESSURE REGULATOR occur.
TYPICAL.
Commercial vs. Hard-piped
and Residential Connectors
Heavy-duty, commercialgrade, flexible appliance gas
connectors are used where
the gas connection is locatedat the rear of the applianceand flexibility is required tohook up the unit (see Figure1). They are designed tostand up to the demands ofa commercial kitchen and
14

Plumbing Systems & Design

Noncommercial (residential) flexible connectors are intended to be installed once
and not be reinstalled, which could cause
the metal to wear out and the connection
to leak. These connectors are not intendedto be repeatedly bent and twisted and canfail due to repeated movement. They are not
NSF certified, and their use in a commercial
kitchen may compromise and violate current
ANSI/CSA and NSF standards and codes
depending on the piece of equipment towhich they are attached.
Connector Installation
Flexible connectors should not be hiddenfrom view, enclosed in chases, or locatedbehind walls in case leakage occurs. They
should be accessible for replacement, ifneeded. For a commercial range, a 6-footmaximum length is permitted. Connectors
are not allowed to be ganged together to getaround the maximum length requirement.

PROVIDE BLOCKING BEHIND
WALL TO SECURE TYPICAL.
RESTRAINING CABLE - TYPICAL.
HOSE GAS CONNECTOR, HEAVY DUTY,FLEXIBLE, CORRUGATED TYPE 304
STAINLESS STEEL TUBING WITH STAINLESSSTEEL BRAID AND ANTIMICROBIAL PVC
COATING - TYPICAL.
SAFETY-SET POSITIONING SYSTEMUNDER EACH CASTER - TYPICAL.

DETAIL OF KITCHEN GAS PIPING REQUIREMENTSSCALE: NONENOVEMBER 2011

TYPICAL GAS FIRED KITCHEN
EQUIPMENT.

Figure 2 Commercial kitchen gas piping requirements

WWW.PSDMAGAZINE.ORG

CHECKLIST FOR FOODSERVICE GAS APPLIANCE SAFETY
Kitchen Safety and Cleanliness Principles
 Appliances must be cleaned.
 Appliances must be able to be moved.
 Appliances need flexible connectors.
 Flexible gas connectors must be durable.
 Flexible gas connector should be certified by NSF International.
Flexible Appliance Connectors
 Lengths shall not exceed 6 feet.
 Connectors shall be located in the same room as the appliance.
 Connectors shall enter a motor-operated appliance with aprotected knockout opening.
 Listed and labeled connectors shall be in accordance with themanufacturer’s installation instructions.
 Listed and labeled quick-disconnect devices shall be used withlisted and labeled appliance connectors.
 Listed and labeled appliance connectors shall comply with ANSI
Z21.69 and be listed for use with foodservice equipment having
casters, or equipment that otherwise is subject to movement forcleaning, and other large movable equipment.

Figure 1 Gas ranges with flexible connectors. Photos courtesy of Dormont Co.

Connectors must be selected to provide the gas demand at
the minimum pressure of the appliance. Figure 2 provides adetail of commercial kitchen gas piping requirements.

RESOURCES
1. NSF International
2. ANSI Z21.69/CSA 6.16: Connectors for Movable GasAppliances
3. ANSI Z223.1/NFPA 54: National Fuel Gas Code
4. CSA B149.1: Natural Gas and Propane Installation Codes
5. International Fuel Gas Code
6. Local codes and standards

Gas Equipment Connection Compliancy
 Utilize a commercial-grade flexible gas connector for allcommercial foodservice gas-fired cooking equipment.
 Don’t use residential-grade flexible connectors in commercialkitchens.
 Ensure that the gas connector is installed in a U shape.
 Don’t hard-pipe the appliance to the gas supply line.
 Use a restraining cable for all flexible commercial-grade gas
connector installations.
 The restraining cable must be connected at all times except when
the cable and gas connector are disconnected for cleaning.
Gas Connector Installation Items
 Ensure that the gas supply and all appliance control knobs areturned off before making connections.
 The connector must not be concealed within or run through any
wall, floor, or partition.
 Connectors shall not come into contact with surfaces attemperatures in excess of 230°F, sharp edges, or wiring.
 The final assembly shall be tested for leaks.
 An accessible manual shutoff valve must be installed at the outletof the gas supply piping system upstream of the connector.
 Connectors are for use only on piping systems having a fuel gas
pressure of 0.5 psi or less.
 Each piece of equipment must have its own shutoff valve.

James Stenqvist, CPD, LEED AP, is a project engineer withDiversified Technology Consultants in Hamden, Conn. For
more information or to comment on this article, e-mailarticles@psdmagazine.org. This article is meant to provide

some basic guidelines. Always check all relevant codes andresources for a particular project.

NOVEMBER 2011

Plumbing Systems & Design15