flue x2 Flashcards
When performing a safety verification of an existing gas installation to NZS 5255 states that the inspection must be supplemented by appropriate tests.
List FOUR tests that this may include.
- Room carbon monoxide testing
- Pressure and soundness testing
- Flue spillage testing
- Combustion testing
State who is to be provided with a copy of the safety verification results.
- The verifier
* The installation owner
List FOUR evaluation methods that may be used to provide evidence of compliance when
undertaking a safety verification of an existing installation.
- Documentation
- Interview
- Visual inspection
- Testing
- Questionnaire
The operation of a range-hood is causing products of combustion to spill from an open-flued
gas appliance.
Describe how a spillage test should be conducted.
- Close the appropriate doors and windows.
- Turn the range hood on.
- Start the gas appliance, let it run for 10 minutes.
- Open a window slowly until the appliance is no longer spilling.
- Measure the opening to work out the required vent size.
When designing a common flue, give THREE reasons why the flue connector rise would need to be increased by 300 mm.
- Outside the limits of Table H1.
- The diameter of the common flue is more than seven times the size of the flue connector.
- If the flue connector has more than two 90° changes of direction.
List FOUR locations where pressure test points are required on an installation.
- Outlet of gas regulators in gas pipework.
- Inlet and outlet of pressure raising devices.
- Outlet of the venting shut off system.
- Inlet of a gas appliance.
- Where a permanent pressure gauge is fitted.
State what is recommended good practice for completing the hot work once the section has been
fully isolated from the existing gas supply.
• Purge the installation with an inert gas.
• Purge the pipe to outside atmosphere.
• Purge 6 m away from ignition sources.
• Purge well clear of any openings into buildings.
• Continuously check air/gas ratios using a calibrated gas detector to indicate when the purge
is complete.
List THREE approved Codes of Practice relevant to gasfitting.
- Excavation for Foundations.
- Hazardous Substances.
- Noise in the Workplace.
- LPG multi-cylinder systems.
Explain the purpose of Approved Codes of Practice.
A set of guidelines to help you comply with recommended standards and requirements
State FIVE factors that need to be specified when selecting a regulator for a gas installation.
- Type of gas being used.
- Inlet or upstream pressure.
- Outlet or downstream pressure.
- Maximum flow anticipated.
- Size of pipework.
- Location.
List FOUR aspects related to a gas installation that must be taken into account before suitability
of a proprietary piping system can be confirmed as specified by AS/NZS 5601 Part 1.
- Measurement systems.
- Gas quality.
- Gas composition.
- Normal and emergency operating conditions.
- Environment conditions.
- Temperature.
- Pressure to which they will be subjected.
List SIX items of information that must be permanently marked on every gas appliance.
- Manufacturer.
- Model Number.
- Type of gas.
- Working pressure.
- Input rating.
- The gas safety compliance label.
A natural draft flue is being designed for a gas appliance.
State SIX factors to be taken into account when calculating the size of the flue.
- Shape of flue – circular or non-circular
- Input rating of appliance
- Length of the flue allowing for lateral runs
- Material of construction – heat loss
- Position – heat loss
- Size of flue spigot on appliance
- Any recommendations of appliance manufacturer
- Termination point
An installation is being converted from LPG to natural gas.
Give TWO aspects of the installation pipework that must be checked and that may need
changing.
- Size/diameter.
* Labelling.
State the specific compliance document that should be used for the installation of commercial catering equipment in a catering vehicle.
AS/NZS 5601: Part 1.
Often when a gas storage water heater is first started the sound of water dripping onto the
burner is heard.
Explain how this water is produced.
The water comes from the flue gases cooling while in the flue and condensing into water, running down the baffle to drip on the burner
Explain why the dripping occurs more at different times.
It occurs more when the water heater is cold because the cold sides of the tank cool the flue gases faster than normal.
A gas-fired storage hot water cylinder is to be installed.
Give FIVE factors that may impact on the efficiency of the system
- Insulation of hot water pipework.
- Location of appliance relative to hot water usage.
- Capacity of heater compared with water demand.
- Pattern of hot water usage.
- Maintenance and servicing of appliance.
- Fluctuating gas supply.
