A self-employed joiner has been sentenced to 300 hours of community service after a gas cooker he illegally installed exploded, severely injuring two householders and causing more than £580,000 worth of damage to four properties.

Alex Irvine was hired by John and Emily Reid to cut out a kitchen unit, worktop and install a new free-standing gas cooker in Kirklands, Renfrew on 31 March 2009.

Mr Irvine was not competent to do the work, nor was he approved by the Health and Safety Executive (HSE) to do so, as he was not registered with Gas Safe Register, the official registration scheme for gas engineers in Britain. It is illegal to carry out domestic gas works for gain or reward without registration.

Paisley Sheriff Court heard that Mr Irvine told Mr Reid he was not qualified to change the gas connection, but that he could still do it. Mr Reid agreed that Mr Irvine would carry out the work for a £60 fee.

After removing the kitchen unit and worktop, Mr Irvine cut a copper pipe to remove an old gas hob, cleaned the end of the cut piece and attached a flexible, rubber hose. The other end of the hose was attached to the new cooker before it was pushed back against the wall.

On 17 April 2009, Mr Reid had used the hob on the new cooker to prepare dinner and was sure he had switched it off. Later that evening the couple were in the living room when they heard a noise in the kitchen, which they believed it to be the oven although neither could smell gas.

Mr Reid went to investigate and heard a noise at the back of the cooker that sounded like a constant whirring or swooshing. He opened the grill door, activating the fan inside the oven, but the noise continued so he put both hands inside and pulled the cooker out about six to nine inches.

The court heard that Mr Reid believed he may have caught the ignition switch with his thumb and there was then an explosion he described as “an almighty bang, a flash of yellow light and a roar”.

Both he and his wife were injured as the gas ignited, suffering burns to their face, hands, arms and neck before fleeing the property. Mr Reid underwent a skin graft on his right hand and Mrs Reid’s eyebrows and eyelashes have still not grown back.

The explosion also caused extensive damage to their home and three other properties. Three of the houses were so badly damaged they had to be demolished and rebuilt. The total cost of this and other damage to property was estimated at £580,000.

Following the incident, an investigation by the Health and Safety Executive (HSE) revealed that not only was Mr Irvine not Gas Safe registered, he had never been in receipt of accredited certification of competence or approved codes of practice certificates of competence.

British Standards and manufacturer’s instructions state that when fitting a gas cooker the connection hose should hang freely and downwards, so that it does not kink. However, the investigation found that the way it had been installed meant the hose was trapped between the cooker, the floor and side unit so it could become kinked when it was pushed against the wall.

Tests revealed that the hose had split at a middle point in the bend of the hose where it had been trapped, on both the inner steel winding and the outer rubber sheath coating. This would have allowed unburnt gas to enter the property.

It was the opinion of HSE experts that the cooker hose had been the source of the gas leak and explosion.

Alex Irvine, 44, of Causeyside Street, Paisley, Renfrewshire, was sentenced to 300 hours of community service after pleading guilty to three offences – breaching Regulations 3(1), 3(3) and 5(3) of the Gas Safety (Installation and Use) Regulations 1998.

After sentencing, HSE Inspector Russell Berry said:

“In carrying out this work while not registered and competent to do so, Mr Irvine put those living in this property and those nearby at risk.

“Thankfully Mr and Mrs Reid escaped with their lives, but were badly injured and four properties seriously damaged as a result of the explosion which was a direct result of the unsafe condition that the gas cooker was left in.

“Any business or sole trader who carries out work on any domestic or commercial gas appliances without being on the Gas Safe Register is breaking the law and potentially putting lives at risk.

“Before having any gas work undertaken homeowners should ensure that they have appointed a gas engineer who is adequately trained and competent to undertake the work. Using a Gas Safe Registered engineer is the only way to make sure your gas appliances are safe.”

Paul Johnston, chief executive of Gas Safe Register, said:

“In the right hands gas is safe but gas work should only ever be undertaken by a suitably qualified and competent Gas Safe registered engineer.