Know how legionella

A more secure pressure testing method – right out of thin air

Throughout most of Europe, pipelines are traditionally pressure tested using water. However, according to some experts, air pressure testing can be a more secure pressure testing method, reducing the risk of both Legionella and water damage, especially for large commercial new builds. 

Don Elworthy is a Senior Contracts Manager at Panks Engineers Ltd in the UK. Panks engages in a wide range of projects from large commercial new builds to residential one-off remodels and repairs. They specialize in building hospitals and schools where hygiene and cleanliness reign supreme. When specifying pressure testing methods, Don always requires air-pressure testing during construction. 

“We section off about 50 metres of pipe at a time and test as construction progresses,” Don explains. “We do it this way for two main reasons. Firstly, we can avoid frozen or burst pipes in winter. And secondly, but most importantly, because it eliminates the risk of Legionella bacteria in the pipes.”

Reducing the risk of Legionella

In the UK, Legionella is governed by seven water companies who require Legionella risk assessment reports for every new build in the country. Don takes full responsibility for these reports and Legionella is always top of mind. If pipes are not dried properly after water-pressure testing, Legionella bacteria can grow. 

“When you pressure test with air, you can skip the time-consuming drying phase, but also be 100% assured that no Legionella bacteria have been introduced to the pipes during construction. This is particularly important in the hospitals and schools that we build.”

Some contractors and installers in the UK will assume the risk of a leak if it means they can save time on the construction process. That is not a risk that Don is willing to take. 

“I insist we pressure-test religiously. Not only does this reduce our damage liability, but it’s also one of our most important selling points to new clients. They benefit from this extra level of security as they can be sure they will not experience a leak that can cause further damage to their asset.”

Reducing liability and damage costs

Over in the Netherlands, leakage is an important topic for insurance companies. Each year, 60,000 insurance claims are filed due to water damage – that’s a value of approximately 200 million euros. Twenty-five per cent of these damages caused by drinking water installations.

Eric van der Blom, Sanitary Specialist at Techniek Nederland, the Dutch business association of technical service providers, installation companies and the technical retail trade. He is closely involved in drafting standards, practical guidelines and quality assuring systems for sanitary installations, including the pressure testing of drinking water installations. 

“We’ve recently rewritten practical guidelines for pressure-testing drinking water installations. With large buildings, water-testing puts you at a big disadvantage because you have to flush the water through the pipelines every week of the build. This costs a lot of time and money.”

Because air pressure testing is done incrementally it saves time on the whole. Each air pressure test takes minimum 130 minutes, compared to only 20 minutes for each water test. However, when you add the preparation time of a water test (the time it takes to get all air out of the system) and the fact that the whole installation needs to be flushed once per week, water testing is more cumbersome and takes much longer. 

“Our view is that pressure testing should be as convenient as possible so that installers and contractors will prioritize it. That’s why we recommend air-pressure testing for larger installations,” says Eric. “In that way, we hope to reduce the annual insurance claims due to leaks.”

By removing a water source, installers can also remove risk from the job site. Water damage is the second most frequent cause of loss during building projects and represents a large percentage of Construction All Risk (CAR) claims. Pressure testing with air means you can be 100% sure that leaks won’t destroy electrical installations, new flooring or fresh drywall. The work environment becomes safer as well.