Natural Gas Technicians Inc. London Ont. 519-858-8924

Identifying common GAS CODE infractions for public safety

Common Gas Line Infractions

The Gas Industry has evolved significantly over the last 15 years. New products and codes have come into effect including standardized piping and fittings.  The Industry regulations require that "any new installation is to conform to the current code standard". Therefore if the standardized identification is not present, it is not approved for use. The following is a summary of some of the most common violations relating to gas lines: flarenuts, copper tubing, gas connectors and csst.

                              improper Copper tubing

The main infractions involve materials being reused and not conforming to the current code standard. Some Technicians improperly reuse GP (general purpose) copper tubing or install ACR (Air Conditioning/Refrigeration) copper tubing because of convenience and they look similar. Both practices are unacceptable and the tubing must be replaced when the appliance is replaced. The correct tubing for aboveground is required to be permanently marked (incised) with the mark “Type GAS” and the name or trademark of the manufacturer at intervals not to exceed 18 inches.

Improper Flare Nuts 

In the Gas Industry flare nuts are fittings that connect copper tubing to a gas system. Since the year 2000, regulators have created a standard to which flare nuts must be manufactured. In addition, it was determined that a flare nut that has been manufactured by "forging" has greater integrity than flare nuts manufactured by "milling". Though sometimes difficult to determine with the naked eye, milled fittings have a distinctive grain created by the direction of the milling. Conversely, a forged fitting has no apparent grain or lines. The pictures below show difference between a milled flare nut (right) and a forged flare nut (left) using a Dino-lite handheld digital microscope at 200x magnification.

Milled flare nut and surface under 200x magnification.

Forged flare nut and surface under 200x magnification

Approved TYPE G/GAS incised into copper tubing

Not approved for gas in Canada, ACR incised in copper tubing

Gas Connectors are manufactured in 1-6 foot lengths and are used to connect movable appliances to gas lines.The most common risk includes (but is not limited to) reusing the gas connector when an appliance is moved from one location to another and/or reusing the connector when a new appliance is being installed.


Gas Connectors (formerly Flex Hoses, Flex Connectors)

CSST was designed in japan for protection against earthquakes. It's flexibility and "ease of installation" made it popular where rigid black pipe was labour intensive and frequently leaked during earthquakes. When brought to North America, it was readily accepted because of the ease of installation and minimal worry of earthquakes. Unfortunately after being installed in millions of homes an ugly secret was proven to be true, csst was susceptible to failure with any surge in voltage applied to the structure. This meant any lightning strikingin the area of a home with csst was at risk of electricity arcing through the csst, thus causing a hole in the csst and igniting the gas at the same time. There are very specific solutions to minimize the potential of a fire and a local infraction expert can help with these issues. There are 2 main ways to avoid a csst fire. Firstly,  make sure the CSST is bonded after the Gas meter and before the first CSST fitting. The second is to ensure separation between the CSST and any metallic parts or systems. For further info call us or Google search, "csst lawsuit" or "".


Corrugated Stainless Steel Tubing

Specific CSST requirements

Csst typically has a yellow pvc or polyethylene outer jacket which mainly serves to protect the stainless steel tube from chemicals and abrasion.  The manufacturer of these products specify how they are to be installed and all installers must be certified by the manufacturer. All parts used with a system must be sourced from the same manufacturers system. In other words don’t mix brand A with brand B.  Below are some abbreviated and paraphrased rules for csst gas line installation. For the complete rules please download a copy of the instruction manual for the brand of csst that is being used.

·         System should be properly bonded and grounded. The bonding conductor shall be no smaller than #6 AWG copper or equivalent.  References irc  2006 G 2411.1, irc 2012 2411.1.1. For more info about grounding and bonding go here.

·         Care should be taken to maintain as much separation as possible from other electrically conductive systems in a building. This includes chimney liners, metal duct systems and electrical cables.

·         Do not install in a chase that includes a metallic chimney liner or appliance vent that protrudes through the roof. If it is necessary to do this then the metallic chimney needs to be grounded and bonded and separation from the csst must be maintained.

·         Rigid termination of tube ends required.

·         Csst is suitable for outdoor use. The outer jack is uv resistant and flame resistant.

·         Tubing must be protected from contact with sharp objects including metal cabinet edges or metal studs edges.

·         Do not bend the pipe too much. Bend radius specifications are in the manual.

·         Support typically- non rooftop non wall cavity- vertical or horizontally- 3/8” pipe support every 4’. Support ½” pipe every 6’. Support ¾” or larger pipe every 8’. Pipe shall be supportive but not restrictive.

·         Holes drilled for pipe should be ½” larger than the pipe.

·         Most CSST fittings are approved for concealed spaces.

·         Manifold stations, shut off valves and regulators cannot be concealed.

·         Strike plates are required.

·         When installed outdoors seal gaps in covering with a self bonding silicone tape.

·         When installed alongside the outside of a structure it needs to be protected inside conduit or a chase up to 6’ in height. Elsewhere it needs to be protected where subject to damage.

·         Cannot be run within ductwork.

·         Must be protected by a watertight conduit ½” larger than the pipe when ran through masonry.

·         Moveable appliance must use a stub out with an appliance connector.

·         Non moveable appliance can be directly connected.

·         Drip legs and shut off valves must be securely mounted.

·         When an appliance has a vent that protrudes through the roof then contact between the csst and the appliance cabinet is prohibited. Certain csst products excepted ( i.e. the black jacketed flash guard type products.)

·         When roof mounted it must be 3” or more off the roof and supported with appropriate clamps and no less than 6’ apart. 1” diameter pipe or greater- 8’ apart.

·         Pad mounted equipment (i.e. not connected to building) must use an appliance connector.

·         Can be used in a gas fireplace. Not a wood fireplace. ( must verify with the manufacturer’s instructions first) Brands vary.

·         Cannot be buried directly. If it is buried then it must be in watertight conduit ½” bigger than the pipe sealed to prevent water entry.Typically no venting is required by the manufacturer in this instance. Check local codes.

·         Regulators in vented area or with vent limiters.

·         Sized and support per manufacturer’s  tables.

·         Repair if crush depth is more than 1/3rd the diameter of piping.

·         System should be tested to 1.5 times the working pressure but not less than 3psi