Raising Awareness of Lpg Pipework Safety

By Jeff Watson, technical manager, UKLPG

Even though the safety of lp gas pipework at industrial premises is always the responsibility of the site operator, lpg suppliers have a key role to play in raising awareness and helping customers.

The serious accident at ICL Stockline Plastics factory at Maryhill, Glasgow, on May 11 2004 resulted in nine deaths and 33 injuries. The basic cause was severe corrosion of the unprotected metallic lpg supply pipework, which leaked lp gas into the building’s basement. This then found a source of ignition and the subsequent explosion triggered the collapse of the building.

It must be stressed that the accident was triggered by the failure of unprotected lpg underground steel pipework. There has been no suggestion that installations carried out using polyethylene pipework alone, which has been the industry’s practice over the last 15 years or so, is at risk.

Whilst awaiting the outcome of Lord Gill’s Public Inquiry, UKLPG members have been working extensively with HSE to raise awareness and develop an action plan for the replacement of unprotected or inadequately protected underground metallic pipework at industrial and commercial premises. So far: ·

• All bulk lpg gas companies have circulated the HSE leaflet Checking Lpg Pipework to their industrial and commercial customers
• UKLPG has prepared and made available via its website extensive guidance on the inspection and maintenance of lpg pipework at commercial and industrial premises
• UKLPG member companies have carried out a ‘desktop’ survey of their customer bases to establish the proportion of their domestic customers (on whom it is far easier to obtain robust data) who have underground metallic pipework
• Member companies are currently carrying out a physical survey, again concentrating on domestic customers.

Some companies, notably Calor Gas and J Gas, have also carried out physical checks on some of their customers’ pipework and Calor has carried out research on the potential risks associated with lpg gas pipework.

The outcome of this work is that the lp gas industry considers that there may be up to a third of installations with some unprotected or inadequately protected buried metallic pipework. The exact distribution of these varies considerably from company to company. It must be stressed that few of these are likely to have all the factors present that contributed to the cause of the Glasgow explosion.

From the work to date, it is clear that two major factors influence the likelihood of corrosion of underground metallic pipework - the age of the pipework and the type of soil through which the pipework runs.

There are also a number of factors that influence the effect of leakage due to corrosion:

• Operating pressure
• Soil type
• Entry into the building
• Presence of a basement or similar void.

Finally, consideration has to be given to the consequence of ignition of the lp gas, such as the structure of the building and how many people are at risk.

Following a number of incidents involving mains natural gas, Advantica has developed a computer model that can give a risk rating for installations. The Health & Safety Laboratory has carried out a research programme to establish whether the model would work for lpg underground metallic pipework, if appropriately modified. It concluded that it would.

Final details of the input requirements are being discussed with Advantica now. Individual bulk lpg companies will then be invited to provide the input data for their industrial and commercial customers so that they can be ranked according to risk.

The purpose of undertaking the risk rating is to formulate a prioritised replacement programme, which will be agreed with the HSE, in the same way as previously undertaken in the natural gas sector. This will be followed by a joint HSE/industry letter describing the action that needs to be taken by the customer to replace their unprotected or inadequately protected underground lpg metallic pipework and a timeframe within which this needs to be done.

Conversations have been and are being held with both HSE and CAPITA (Gas Safe Register) to facilitate the availability of appropriately qualified lpg gas installers to meet the expected demand.

Though the current programme is centred on industrial and commercial premises, a similar risk rating will also be applied to the domestic sector on the basis of information from the lp gas supply companies. Whilst the responsibilities are clearly on the site operator for industrial and commercial premises, the situation for domestic customers may be less clear. Most customers own their lpg pipework and therefore have responsibility for it. However, there are a significant minority who do not. Individual lp gas companies will need to consider how to handle this. UKLPG continues to hold discussions with HSE to consider the best way forward and give appropriate guidance.

As has been said repeatedly, unprotected or inadequately protected lpg underground metallic pipework remains one of the biggest challenges the industry faces.

Contact UKLPG on 02476 711601 www.uklpg.org

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