Embedded Files
Viper Gas resources
British standards-
British standards-
BS 6891- Installation of low pressure gas pipework of up to 35 mm (R1¼) in domestic premises (2nd family gas) — Specification
BS 1387 - steel pipes of a medium weight
BS EN 1057 - light gauge copper tubes
In addition
In addition
GSIUR 1998 - Safe installation and use of gas systems and appliances
Building Regulations - various
Pipe sizing©
Pipe sizing©
Installation pipework / Materials
Installation pipework / Materials
Copper capillary or solder ring fittings are suitable for domestic installations, but not all fluxes are suitable for the soldering process.
Low-carbon steel is best for resisting mechanical damage. A tapered BSPT thread fits into apparent thread socket to form a seal. Hemp should not be used.
PE( Polythene) pipework is mainly used for underground supplies. If it does come into a house, it must be protected against UV. It can be joined by compression or fusion welding.
This material is called corrugated stainless steel tube and has the same resistance as copper. It requires special fixings but can be adapted to fit any other pipe used for gas installation.
Caution - buried pipework
Caution - buried pipework
A cover of 40mm below concrete slabs in an area where people walk or 375mm below any open ground and drives will be enough to prevent mechanical damage to buried gas pipework.
Great care should be taken to protect pipework which is buried in screed any from mechanical damage. Generally, a minimum cover of 25mm from the surface will be sufficient.
Common pipework faults
Common pipework faults
The sleeving of a pipe travelling through a wall must be able to contain gas and should be sealed at one end only, so the gas escapes to the atmosphere. There should also be sealing around the sleeve itself. No unprotected pipe should travel through a cavity wall.
Open ends- An open and on a gas pipe is considered immediately dangerous (ID) and RIDDOR reportable.
Inappropriate use of a fitting-
Inappropriate use of a fitting-
All fittings connecting gas pipes and appliances must be 'appropriate fitting' (GSIUR) regulation 2-
a) has been designed for the purpose of effecting a gas tight
seal in a pipe or other gasway,
(b) achieves that purpose when fitted, and
(c) is secure, so far as is reasonably practicable, against
unauthorised opening or removal;
Tightness testing of natural gas
Tightness testing of natural gas
Documents-
IGE/UP/1B/Ed3 -The new standard for domestic gas tightness testing
Tools for tightness testing-
Manometer/
Leak detection fluid
Slotted screwdriver
Stopwatch
Lint free cloth
Always ensure that your test equipment is in good condition so
that readings can be clearly seen thereby, enabling an accurate test
to take place.
Leak detection fluid used to ascertain if any joints that have been broken are gas tight after carrying out a tightness test, usually sprayed around the test nipple on the gas meter.
A slotted screwdriver is used to remove the test nipple from the meter, rather than a spanner as the leverage on a spanner could damage the meter/nipple.
Image shows a sheared off test nipple.
Stopwatch is used to time the stabilisation and test period and the cloth is used to clean and wipe away the leak detection fluid.
Let by and tightness testing using an analyser
Let by and tightness testing using an analyser
It is essential that the installation is visually inspected before progressing with a gas tightness test. A check could reveal dangerous situations such as open ends or plastic caps on pipework.
An image of a domestic regulator, fitted with a seal. It is imperative as part of the visual check the engineer checks for the seal and if it is missing they must contact the gas supplier.
Emergency Control Valve
Emergency Control Valve
The the ECV stands for the emergency control valve and sometimes it is called the MECV, which is meter emergency control valve. It is essential that the valve falls to the off position, as shown, because the whole system is isolated from this point. The corrugated stainless steel tube (CSST), commonly known as the anaconda, is labeled showing the correct direction of operation of the lever.
Procedure-
Procedure-
Let by test -
The purpose of the let by test is to check the integrity of the valve to see if it is leaking when in the closed position.To carry out the test, remove the test nipple and carefully attach the manometer hose to the test point. Slowly open the ECV and raise the pressure in the manometer to 10mbar.
When the pressure has reached 10mbar, close the ECV and test the pressure for one minute.If there is any perceptible rise (0.25mbar)* during that period, it is deemed that there is a let by from the ECV. If it is safe to do so, loosen the connection down stream on the ECV and spray leak detection fluid on the exposed inner valve to see any evidence of leakage.If leakage is confirmed inform the gas supplier who will repair or replace the valve
Procedure-
Procedure-
Tightness testing-Temperature stabilisation
The purpose of the stabilisation test is to ensure that temperature rise or fall in the pipework does not adversely affect the tightness test reading.A once a successful let-by test has been achieved, for example, if there is no perceptible rise on the manometer, then raise the pressure to 20 mbar by slowly opening the ECV. Once the pressure has been reached close the ECV and test for one minute.
Procedure-
Procedure-
Tightness test-
The purpose of the tightness test is to ensure test the integrity of a gas installation. Once a successful temperature stabilisation test has been achieved, retain or readjust the pressure of 20 mbar, proceeding with the tightness test for two minutes, and record any movement of the gauge. Any pressure drop detected should be checked against the permissible drops which are shown in IGE/UP/1B/Ed3 2012 table 3.Once a successful temperature stabilisation test has been achieved, retain the pressure of 20 mbar, slowly opening the ECV, if there has been any fluctuation of pressure, and closing it again once 20 mbar has been reached.This time test for two minutes and record any movement of the gauge.
Key points to remember
Key points to remember
Tightness testing procedure of installations of pipework up to 35mm is covered in IGE/UP/1B/ ed 3: 2012. For larger pipework, ie 42mm or with systems containing over 0.035m3 of gas, the testing procedures are covered in IGE/UP/1A
Different types of meter permit pressure drops when testing providing there is no smell of gas
A tightness test means that the installation pipework and the appliances up to the gas valve are included. When testing pipework only there is no permissible leakage.
Electronic gas meters require calibration every 12 months to ensure they produce accurate readings
Even after a successful tightness test, sometimes components such as gas valves on appliances can leak gas during operation, if this happens then check the component with leak detection fluid to find the source of the leak
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