Installation of Gas Pipes

Installation, repair and replacement of gas piping or appliances shall be performed only by a qualified installing agency or gas fitter.

Protection of piping

Piping shall be buried to a sufficient depth or covered in a manner so as to protect the piping from physical damage. Measures should be taken to protect the piping from physical damage when it passes through flower beds, shrub beds and other such cultivated areas.

Protection against corrosion

Gas piping in contact with earth or other materials which will corrode the piping shall be protected against corrosion in an approved manner. When dissimilar metals are joined underground, an insulated coupling shall be used. Metallic piping shall not be laid in contact with cinder or ash.

Piping through foundation wall

Underground gas piping, when installed below grade through the outer foundation or basement wall of building, shall be either encased in a sleeve or otherwise protected against corrosion. The piping or sleeve shall be sealed at the foundation or basement wall to prevent entry of gas or water. 

Piping underground beneath buildings

If the laying of gas piping underground beneath buildings can not be avoided, the piping shall be encased in a conduit. The conduit shall extend into a normally usable and accessible portion of the building and, at the point where the conduit terminates in the building, the space between the conduit and the gas piping shall be sealed to prevent the entrance of gas from any possible leakage. The conduit shall extend at least 100 mm outside the building, be vented above grade to the outside and be installed in such a way as to prevent the entrance of water and moisture.

Building structure

The building shall not be weakened by the installation of any gas piping. Existing beams and joists shall not be cut or notched.

Piping supports

Gas piping in buildings, shall be supported with pipe hooks, metal pipe straps, bands or hangers of an approved type and material suitable for the size of piping, and located at specified intervals so that the piping cannot be moved accidentally from the installed position. Gas piping shall not be supported by other piping.

Piping entrance to buildings

When gas pipe enters a building through a wall or floor of masonry or concrete, it shall be sealed against the entrance of water, moisture or gas.

Piping in floors

Piping in solid floors, such as concrete, shall be laid in a channels in the floor suitably covered to provide access to the piping with a minimum damage to the building.

Changes in direction of gas pipe shall be made by the use of approved fittings, factory bends or field bends. Field bends shall be made by employing approved procedures and equipment.

Gas piping inside any building shall not be run in or through an air duct, chimney or gas vent, ventilation duct or elevator shaft. Gas piping shall not be taken through inaccessible or concealed areas where its condition cannot be inspected and accumulation of gas due to undetected leakage may create a dangerous condition.

Provides Drips Where Necessary

A drip shall be provided at any point in the line of pipe where condensate may collect. When condensation is excessive, a drip should be provided at the outlet of the meter. This drip should be so installed as to constitute a trap wherein an accumulation of condensate will shutoff the flow of gas before it will run back into the meter. All drips installed shall be readily accessible to permit cleaning, inspection or emptying. 

Cap All Outlets

Each outlet, including a valve or cock outlet, shall be firmly closed gas tight with a threaded plug or cap immediately after installation and shall be left closed until an appliance is connected thereto. Similarly, when an appliance is disconnected from an outlet and the outlet is not to be used again immediately, it shall be firmly closed gas-tight. The outlet shall be closed with tin caps, wooden plugs, corks or by other improvised means or objects. Use of a listed quick disconnect device is acceptable.

Prohibited Devices

Any device that will reduce the flow cross-sectional area or otherwise obstruct the free flow of gas shall not be inserted or placed inside the gas pipe or fittings.

Branch Pipe Connection

All branch pipe connections and outlets shall be taken from the top or sides of horizontal lines and not from the bottom.

Electrical Bonding and Grounding

The gas piping shall be electrically continuous throughout its length and earthed except in sections where cathodic protection system is used for protection against corrosion. The piping shall not be used to ground any electrical equipment.

Distance from Electrical Wiring

The distance between the gas piping and electrical wiring system shall be at least 60 mm. They shall be fixed to prevent contact due to movement. The gas piping should be installed below the electrical wiring. 

Distance from Stream piping

The gas piping and stream piping,if installed parallel, shall be at least 150 mm apart. The gas piping should preferably be installed below the steam piping. 

Gas piping to be Graded

All gas piping shall be graded not less than 1 in 750 to prevent accumulation of condensate or liquids in the line. All horizontal lines shall graded to risers, and from the risers, to the meter, or service regulator when there is no meter, or to the appliance.

The gas piping shall be painted red in order to differentiate it from other piping. Where the piping is exposed to sun rays, it shall be painted silver gray.

Documentation shall be maintained for all gas supply installations.

Check for leakage of gas supply system

Before supplying gas under pressure into any piping, all opening and outlets from which gas can escape shall be closed.

Check for leakage

No match, flames or other sources of ignition shall be used to check foe gas leakage from meters, piping or appliance. Checking for gas leakage with soap and water solution shall be recommended. Artificial illumination used in connection with a search for gas leakage shall be restricted to battery operated flashlights (preferably of the safety type) or approved safety lamps. in searching for leaks, electric switches should not be operated. If electric lights are already turned, they should not be turned off. An individual shall not work alone in any situation where practice desires that two or more persons are necessary to carry out the work safely. Smoking is strictly prohibited.

Checking for leakage with Meter

Immediately after supplying gas into the piping, the system shall be checked to ascertain that no gas is escaping. This may be checked by carefully watching the test the test dial of the meter to determine whether the gas is flowing through the meter. Under no circumstances shall a leakage test be performed using a gas meter without ascertaining the operability of the meter immediately prior to such test. The details of installation of gas pipes are described in previous post.

Checking of leakage not using a Meter

This can be performed by attaching to an appliance orifice, a manometer or equivalent device(gauge) so that it can be read in increments of 2.5 mm water column and momentarily turning on the gas supply and observing the gauging device for pressure drop with gas supply shutoff. No drop in pressure shall occur during a period of 3 minutes thereafter.

When leakage is indicated

If the meter test hand moves or a pressure drop on the gauge occurs, all appliances or outlets-supplied through the systems shall be checked to ensure that they are shut off and do not leak. If they are shut off firmly there is a leak in the piping system. The gas supply shall be shut off until the necessary repairs have been made, after which the test specified above shall be repeated.