Gas FAQs: Distribution System Safety
[ Last Updated 3 July 2007 ]
Distribution System Safety
Q. What Should I Do If I Smell Gas Out in the Street?
A. You should immediately:
- vacate the area, and alert others not to enter,
- contact your gas retailer (or ring the gas emergency number in the front of the telephone book), and
- keep flames, cigarettes and electrical equipment away from the area.
Q. What Should I Do If I Want to Dig Around a Gas or Other Utilities Service Connection?
A. Contact the local council who may be able to advise you of the utilities in the area. Then contact the owners of the utilities and request they identify where the utility is located. They would locate the pipe by providing a plan, or they may wish to have their technical people available or on site when you do the digging.
Q. Is it Safe to Live Close to a Gas Distribution System or Pipe?
A. Gas distribution systems in New Zealand are generally new and therefore safe to live close to. However, homeowners need to be aware of two matters if they live close to a distribution system:
- If there is an accidental leak (e.g. caused by a digger hitting a pipe), a homeowner should close all doors and windows so that gas does not enter the house, and call the Fire Service. If the amount of leakage is very high and there is a strong smell of gas, you should evacuate your home and move to a safe place, well away from the leak.
- There have been cases where gas has leaked into a building through unused pipes or underground channels and exploded, even though the building was not connected to a gas supply. Therefore, if you live close to a gas pipeline, any smell of gas should be considered as serious and you should call the Fire Service or the local gas supplier to check for the presence of gas.
Supply Quality
Q. Does New Zealand Have a Different Gas Composition From Other Countries?
A. Natural gas composition in NZ may be different from that in other countries. If you bring an appliance from overseas you should ensure it is suitable for NZ gas by having it tested or assessed.
LPG composition may also be different but, if your appliance has been tested for both propane and butane use in the country of origin, it should operate safely in NZ with LPG.
Q. Does Gas Have a Smell?
A. Gas, as produced generally, is odourless but the Gas Regulations 1993 require fuel gases to be odorised, having an unpleasant smell for safety purposes. If gas has been released, but you are unable to smell it, you should consider consulting a craftsman gasfitter to install a gas detector.
Q. Does the Chemical Composition of Natural Gas Change, and Does this Create Safety or Efficiency Problems for Me?
A. The composition of both natural gas and LPG can change, but appliances are generally tested with gases representing a range of compositions that they may be exposed to. The Energy Safety Service monitors this quality to ensure the chemical composition does not go beyond acceptable safety limits.
Q. How Does Quality of Supply (Pressure, Interruptions and Impurities) Affect Me?
A. Low pressure can affect households in two ways:
- Lower than contracted pressure means that you are paying more for your gas, as the meters (domestic and most commercial premises) do not have any correction mechanism for pressure fluctuations.
- Low pressure could affect performance of the installation and appliances. It could lead to carbon monoxide generation, and even shutdown of some gas appliances. If these appliances do not have flame-failure protection system and are not turned off manually, they could fill the house upon restoration of pressure. This scenario has a low possibility of occurrence, as gas companies generally are very conscious of the importance of maintaining gas pressure.
Pressure that is too high can also be dangerous as, in cases where appliances do not have a protection system for higher pressure, a fire hazard exists due to the presence of a large flame and any nearby combustible material. Generally, sufficient precautions are taken in the design of pressure-control systems and gas installations to ensure high-pressure situations rarely occur.
In the case of a planned interruption to the gas supply, the gas supplier will inform you and control the process. In the case of unplanned interruptions (e.g. loss of pressure due to an earthquake or line rupture), you must turn off the main gas valve and inform your gas supplier so they can fix the problem.
In New Zealand, fuel gases have few impurities. However, if you have any concerns about the quality of the gas you are supplied with, you should contact the gas supplier and, if not satisfied with the response, contact Energy Safety to take the matter further.
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