The following information is provided to explain the recent alteration to how incorrectly sized open-flued and flueless gas appliance ventilation should now be being classified by all CORGI Registered Gas Installers.
To standardise the way in which gas businesses and their operatives deal with unsafe gas installations that are encountered, the Gas Industry produces a document which provides industry with agreed guidance to gas operatives on how to deal with unsafe situations they encounter in the course of their work. This guidance is titled the Gas Industry Unsafe Situations Procedure (GIUSP) and was first published by CORGI in 1998.
Changes to Classification of Undersized Combustion Ventilation
One of the most significant alterations in the Fourth Edition of the GIUSP was the introduction of a stepped change to the way in which undersized and incorrectly configured open-flued and flueless gas appliance ventilation is dealt with. It should be clearly understood that the formula for calculating the minimum ventilation requirements for open-flued and flueless appliances has not significantly changed for some years. This formula can be found in British Standard BS 5440-2: 2000 – Installation and maintenance of flues and ventilation for gas appliances of rated input not exceeding 70kW net – Part 2: Specification for the installation and maintenance of ventilation for gas appliances, which was originally published in 1976.
Equally, it is important to recognise that for any gas appliance to burn its fuel correctly, it needs sufficient oxygen to enable the gas to burn safely, avoiding carbon monoxide (CO) from being produced in the combustion products (fumes). A ratio of 10 volumes of air to 1 volume of gas (Natural Gas and Liquefied Petroleum Gas (LPG)) is required to ensure safe combustion and also to ensure that in the case of open-flued appliances, that the chimney/flue to which the appliance is connected safely evacuates the combustion products to outside air. Hence the importance of providing correctly sized purpose provided ventilation to open-flued and flueless gas appliances.
As a result of statistical information collected from gas incidents which have occurred as a result of inadequate ventilation, it was decided to reassess the guidance previously given to gas operatives. The result being that, undersized ventilation situations should be re-classified.
Agreed Wording for Customers
The following suggested wording has been provided to Registered Gas businesses, by CORGI, to explain to customers that although industry requirements for purpose-provided ventilation for open-flued and flueless appliances has not altered, the way in which the Gas Industry now recognises the risks presented and the way that gas operatives should now be dealing with these situations has altered:
“During our/my recent visit to your property, it was identified that the ventilation provision to your open-flued/flueless gas appliance is insufficient to meet the current gas Industry Standards. The operation of the appliance was checked during our/my visit and it was confirmed that at the time of testing, it was functioning safely”.
“Due to changes in the Gas Industry Unsafe Situations Procedure, your gas appliance installation is currently classified as “Not to Current Standards”. However, from the 1st June 2008 this classification will alter and subsequently be considered to be “At Risk” and from 1st June 2008, you will be advised not to use the appliance until the ventilation provision has been improved to meet the latest industry requirements”.
“In the interests of your safety, we/I recommend that improvement to the ventilation provision be carried out at the earliest opportunity, to ensure your continued safety and the safe operation of your gas appliance.”
If you require any further clarification or help regarding the above information please do not hesitate to contact CORGI Technical Services via telephone on 0800 915 0499 or by e-mail.