Gas police

It seems basic, but the gas regulator does a very important job

Gas regulators are such an integral part of camping equipment that most of us scarcely give them a second thought. Most camping gas stoves and fridges have one: It’s a round device that’s just a bit smaller than the palm of your hand.

It looks a bit like two saucers placed rim to rim, with a gas hose on either side. These hoses connect your gas bottle to a gas appliance. Regulators usually fit directly onto the gas bottle but on some they may be positioned a few centimetres away from it.

Gas regulators have not been manufactured in a SA for a number of years. Those available today (there are about eight brands on the market) come from Europe or China. All these imported regulators must be approved by our authorities before they may be sold locally.

Kobus Voigt is the owner of Novida Testing Services in Pretoria and he’s the man who decides which regulators are up to standard for sale. Kobus got the green light from the South African National Accreditation System (Sanas) to test gas regulators and is the only one in the country with the authority to give a gas regulator the thumbs up. He used to work at the SABS, but since 2004 has focused on testing regulators.

We chatted to Kobus about testing and what it takes to be an approved regulator.

FIRST THINGS FIRST

Kobus says the regulators that campers and caravanners use are known as 2,8 kpa low pressure regulators. When it comes to gas, we refer to kpa (kilopascal – the international standard unit of pressure) and not bars of pressure.

Not all regulators are created equal. For example, in America you can buy 3,7 kpa and 5 kpa units. Kobus says this is because we don’t use the same type of gas as the Americans do. They use either butane or propane gas, while we burn LP gas (liquefied petroleum gas) – a combination of butane and propane. In an ideal world it would be an equal 50-50 mix, but in South Africa the proportion is closer to 70% propane and 30% butane.

The pressure in a gas bottle can vary between 100 kpa and 700 kpa (or between 1 and 7 bars). If you consider that you put an average of 2 bars into your tyres, you’ll appreciate just how much pressure the gas in that gas bottle is under. The regulator has to deliver a steady gas flow of 2,8 kpa as the cylinder gradually empties.

This is very low pressure – even lower than the pressure when you blow out all the candles on your birthday cake. A regulator is also designed to allow a specific amount of gas to flow through in a particular amount of time, for example 1 kg gas at 2,8 kpa per hour.

HOW DOES THIS WORK?

One side of the regulator is attached to the gas cylinder and the other to the appliance. The gas flowing into the regulator as a result of the pressure in the cylinder, exerts pressure on a diaphragm in the regulator.

Behind the diaphragm is a spring that pushes back to let 2,8 kpa gas through and cut off the supply to the regulator proportionally by means of a valve called a poppet valve. The looser the spring, the lower the pressure on the outlet side; the tighter the spring, the higher the pressure. Some regulators have a mechanism in the middle that you can use to adjust the spring, but this is not a good idea. If you fiddle with the regulator and something goes wrong with your cooker, the insurance company could refuse to pay out.

WHAT’S WRONG?

You’ll immediately notice if there’s something amiss with the regulator – the flame won’t burn properly. If the flame on your gas stove looks tired and yellow, the pressure may be too low. And if the flame burns some distance away from the burner, the pressure may be too high.

DO YOU GET DIFFERENT TYPES?

There are basically only two types of regulators that’ll fit a camping gas cylinder: A bullnose regulator that fits 9 kg gas canisters or larger, with a 5/8” BSP left-hand thread; and a swivel regulator, which is used on gas canisters smaller than 9 kg and has a 3/8” BSP right-hand thread.

He doesn’t often come across regulators with defects, says Kobus, but sometimes the thread is too small, or the output pressure is too low.

HOW THE TEST WORKS

The comprehensive testing they do takes about four weeks and a regulator must comply with specific standards.

IT MUST HAVE A REGULATOR

Regulators sold in South Africa must comply with the following requirements: The locking nut must be made of metal to ensure a good, tight seal. Non-metal parts that come into contact with the gas may not be porous and must have a specified level of hardness. The regulator must have a hole on the spring side of the diaphragm. . An 8 mm gas hose must fit on the outlet nozzle, and there must be a thread on the other side. Certain info must be printed on every regulator, including the brand name; the direction of the gas flow (indicated with an arrow, for instance); the outlet pressure (2,8 kpa); the gas flow, expressed in kg/h or g/h; the month and year of manufacture; and the specific model. The regulator itself must be accompanied by a leaflet that includes the following info: The regulator is for use with LP gas only; if the spring pressure has been preset, you may not tamper with it; the address of the agent or manufacturer; and how the regulator must be attached to the gas cylinder and hose.

SIGNS OF THE TIMES. A gas regulator must have certain info printed on it, such as the outlet pressure and direction of the gas flow.