Maintenance problems with water mist

Maintenance problems with water mist

Stewart Kidd, a loss prevention consultant with extensive experience of managing fire safety and security in the Middle and Far East and Chair of the British Automatic Fire Sprinkler Association Water Mist Working Group in the UK, examines the concerns which may be inhibiting the wider acceptance of water mist.

While it is now widely acknowledged that water mist as a technology is a valuable additional agent in fighting fires in buildings and protecting plant, there are still concerns which may be inhibiting wider acceptance. These can be summarised as:

  • The lack of real fire experience when compared with sprinklers where there is 130 years of solid data and experience
  • An absence of a corpus of experienced installers with third party certification
  • The use of uncertificated equipment, especially nozzles not tested to an appropriate standard

Unlike sprinklers, water mist systems and their components are not inter-operable (analogous to closed protocol fire detection systems)

The solution to the first three of these problems can be encapsulated in the advice offered by the British Automatic Fire Sprinkler Association (BAFSA) which makes it clear what is needed in all installations – not only water mist but all fire suppression systems – is they should meet three tests: 

  1. The system should be designed in accordance with an appropriate national or international standard.
  2. The system components should have been tested and listed in accordance with a specific test standard.
  3. The installer should be in possession of third-party certification for the work undertaken. 

The fourth problem is much the most challenging … over the past three years BAFSA has seen a steady increase in questions from housing providers, homeowners and landlords who have installed pre-engineered water mist packages. Typically, the question put to us is:

 ‘I live in a flat which is fitted with a water mist system installed by a company which is no longer trading. The system has not been serviced for some time and I don’t believe it’s working. I have spoken to several fire protection companies but no one is able to help me – the only concrete suggestion being ‘rip the system out and start again’.

In one recent case, the problem is further complicated by the fact the orphan installation is a high-pressure cylinder system. Setting aside the wisdom of installing such systems in flats (where low-pressure water mist or sprinklers will do an equally good job), there is the thorny subject of the requirements of the Pressure Systems Safety Regulations 2000 and the Pressure Equipment (Safety) Regulations 2016. Many smaller fire protection companies do not seem to be aware of their obligations under these regulations, for example, the need for cylinders to be removed and pressure tested after 10 years. 

 Mention of legal obligations reminds me of the fact that if a water mist or sprinkler system serviced has been installed for life safety purposes but is non-operational then a criminal offence under Article 17 of the Fire Safety Order (or its Scottish equivalent) has been committed. 

Both the owner of the premises and the relevant contractor may share legal responsibility.

Other impacts of the lack of inter-operability can be seen in enquiries from an operator of sheltered housing and a social housing provider. Both had procured high-pressure water mist systems which, after less than 3 years’ service, were suffering from leaky nozzles. Neither system owner appears to have been notified that only the system installer should service the systems. In both cases there was a legal requirement to maintain the systems and reputable fire protection contractors with LPCB certification were engaged for this. 

In both cases it quickly became apparent that replacement nozzles were not available and eventually, when these could not be procured from any source, the original installer was called to site. This resulted in significant claims against the building owners for alleged damage.

This lack of inter-operability which ties an installation to its original supplier generates other concerns, most notably in the costs of maintenance and spares where the installer or system manufacturer is at liberty to charge whatever the trade will bear. 

There is considerable experience of this in the fire detection industry where many suppliers only offer closed protocol systems. 

The impact of this lack of inter-operability in water mist systems is generally directly analogous with the problems in closed protocol fire detection systems. However, it is certainly true that having to replace a water mist system will be a much more expensive and disruptive undertaking than replacing a fire detection system where existing cabling (or at least cable routes and conduit) can be re-used.

BAFSA has expressed many times that the intensely proprietary nature of water mist system design is at once an advantage (systems are bespoke to a specific risk) and disadvantage (a building owner is tied forever to one supplier). This, coupled with the ability of the installer and manufacturer to bypass requirements of the published standards via the DIOM remain a significant obstacle to wider acceptance of water mist technology. The fact that some water mist system installers may not be financially secure reinforces the problem.

 Many fire systems professionals are increasingly adopting a view that unless a robust certification standard can be agreed and enforced by a credible third party scheme then the undoubted advantages of water mist as a fire suppression medium will never be realised. 

 Recent suggestions have included the benefits of an equivalent document to LPS 1048 for water mist systems. This could be utilised by the three existing UKAS accredited bodies which can undertake system and installer assessments and provide regulators and insurers as well as end-users with a significant degree of comfort. 

This article first appeared in Sprinkler Focus November 2022.