Testing and purging for gasfitting

Testing and purging for gasfitting

by Ice one

​Testing and purging

• ​In this lesson we are going to give you a intro into testing for soundness and how to purge safely.

• ​As a gas fitter these are one of the most important things we need to know to keep the community safe.

​Testing for soundness

• ​When working in a property as a gasfitter we have to make sure that property is safe, it becomes our responsibility.

• ​Testing for soundness is one of our most important things we can do, not just to make sure the property is safe for the owner but also to make sure its safe for us to work in.

​Testing for soundness

• ​When testing for soundness we have different tests for different circumstances, below are a few of the tests.

• ​Pipework test, Testing the pipework to the property with no appliances connected.

• ​Installation test, Testing the pipework and the appliances to the last control device.

• ​Leakage test for existing installations.

​Stabilization test

• ​This is carried out before any test is carried out.

• ​This is a 2 minute test.

• ​This is for the temperature of the testing medium to steady out, we do this as different temps / weather can effect our tests in different ways.

• ​IT is not to be included in the 5 minute tests that follow below.

​Pipe work test

• ​As covered on the previous slide this is for pipe work only and appliances must be isolated by a isolation valve or removed from the pipework system.

• ​This test can be done for new pipework and existing pipework.

• ​There can be no drop on this test

​Installation test

• ​This test is for when a gas appliance has been installed to the gas pipe work system.

• ​In this test the isolation valves previously mentioned will now be open and the appliance shall only be isolated at its last control device IE Hob control knob off.

• ​Again no leaks allowed.

​Existing Installation test

• ​This is a test for existing installations, for example you may have turned up to the property for a gas smell or leak.

• ​One thing different with this test is you are allowed a small leak.

• ​On the next slide is a table with the allowances

​Existing installation test

Below is a table with the leak allowance

​Remember this is only for an existing installation,

​Testing instruments

• ​To test gas installations and appliances there are different devices you can use.

• ​Each device has a limitation though and you need to know which device to use.

• ​For example you would not use a 7 KPA rated u gauge on a 10 KPA rated pipe line.

• ​And you would not use a bubble leak detector to set your appliance pressure.

​Testing instruments

​Testing instruments

• ​As a rule of thumb for testing a installation we should be using and u gauge or digital manometer.

• ​We use these as they are very reliable and the digital one being very accurate.

• ​Digital manometers are really good at setting appliance pressures as most of the go to two decimal point IE 2.75.

​Testing instruments

• ​We also have other components we can use to detect gas leaks.

• ​Electric gas sniffers

• ​Leak detection agents IE soapy water.

• ​However we need to make sure we use the right ones.

  ​For example when inspecting for leaks on a electric gas appliance you would not use leak detection agent you would use a gas sniffer, to avoid electric shock.

​Purging

• ​As gasfitters purging is really important, on these slides we will go over what it means to us.

• ​Purging in its most basic is really removing a gas or debris from a pipe and replacing it with another.

• ​When we purge as gasfitters wanting to remove gas from a pipe work we use an inert gas.

​Purging

• ​What is a inert gas? Well putting it simply it is a gas that will not aide combustion, as gasfitters we mainly use nitrogen to purge gas out of lines as this does not aide combustion.

• ​How ever this is not always the case, as we also need to purge air out of the line and replace it with gas for safe combustion.

​Purging

• ​When purging there are a couple of things we need to take into consideration for it to happen safely.

• ​Number one thing being where are we purging to? We need to make sure the area is well ventilated, If inside make sure windows and doors are open.

​Purging

• ​If the installation your are purging is over 30l in volume in the pipe system a written test procedure is needed see the attached caption.

• ​Again with purging we just need to make sure we are being safe and if in doubt recheck to codes for advice.

​Purging

• ​The other things we need to take into consideration is ignition sources. These could be many things a couple of examples are light switches, electronic tools and live flames IE lighters or matches.

• ​Look into your NZS:5601.1 for the purging processes.

​Purging

• Remember D2 also covers off purging for appliances with specific flame failure safeguards

• Pay attention to theses clauses

• D3

• D4

• D4.3

• D4.4

• D4.4.3

• D6
  

Self Check​

​Please answer questions below

Multiple Choice

When carrying out a pipework test what pressure do we use?

• 2.5kpa or operating pressure.

• 7kpa or 1.5 times the operating pressure.

• 2.75 kpa.

• Any pressure as long as you can here the leak.

Multiple Choice

When carrying out a installation test what pressure do we use?

• 2kpa or operating pressure which ever is greater.

• 1500 kpa.

• What ever the appliance tells you to test at.

• 7kpa or 1.5 times the operating pressure.

Multiple Choice

Can an existing installation test have a leak?

• Yes

• no

Multiple Choice

How would you find out the amount it can leak by?

• As long as it does not smell to bad all good.

• Use a leak detector on a low setting mode.

• Table E1 in the ASNZS:5601:1

• It cant leak.

Multiple Choice

When testing for soundness how long do we test for?

• 7 minutes.

• 2 minutes

• 15 minutes

• 5 minutes.

Multiple Choice

What is the test called that we do before testing for soundness?

• Temperature test.

• Ozone test.

• Stabilization test.

• Pressure test.

Multiple Choice

As per the previous slide when do we need to do this test?

• Every time before we carry out soundness tests.

• Only if the weather is extreme conditions.

• If your working at high altitude.

• Only if your boss advises you to.

Multiple Choice

Again going off the slide before how long does the test need to go for?

• 5 min.

• 7 min.

• 2 min.

• 15 min.

Multiple Choice

When testing for soundness we can test straight from the meter?

• True

• False

Multiple Choice

When purging and your pipe work volume is over 30 l what do you need to do?

• Extra ventilation must be supplied.

• A written test procedure is required.

• Work safe must be informed.

• Have the fire brigade onsite.

Multiple Select

When purging what are some of things we need to take into consideration?

• Ignition sources.

• Ventilation.

• Appliance data badge.

• What type of gas we are purging.

Multiple Choice

What does inert mean?

• Means the gas has high pressure.

• Means it will combust quickly.

• Means it wont aide combustion, wont combust.

• Means it is clean.

Multiple Choice

Which of the following is a inert gas?

• LPG

• Natural gas

• Nitrogen

• Helium

Multiple Select

Why do we purge?

• To remove dust/ debris.

• To remove unwanted gases in pipework.

• To provide gas directly to the appliance.

• To reduce the risk of dangers IE explosions.

Drag and Drop

Which appendix covers off purging an appliance with an electronic flame safe guard​ ​

Placeholder

Drag these tiles and drop them in the correct blank above

D5.5

D4.4

D4.4.3

E3

Multiple Choice

An existing pipe section 50mm in diameter and 32mtrs long needs purging to remove the gas, what gas do we use

• OXYGEN

• AIR

• ARGON

• NITROGEN

​Well Done
Thank you for completing this lesson