Making a DIFFerence

Integrated automatic firefighting systems, already known in the offshore fire protection market, are increasingly being used on hospital helipads. Thanks to recent technology, foam or water, usually sprayed from a series of nozzles integrated into the helipad, will help keep the helipad and building safe in the event of a fire. How do such systems work, and what are the benefits? Femke van Iperen found out
King’s College Hospital (KCH) serves a trauma population of some 4.5 million people across southeast London and Kent, UK. In October 2016, the hospital introduced to the UK the first Civil Aviation Authority-certified onshore rooftop helipad with a deck integrated firefighting system (DIFFS). In the event of a fire, the new system will automatically spray a foam and water mix from a series of nozzles installed in the helipad, aiming to bring a fire under control within a minute.
It’s a proven technology that not only increases safety, but also reduces staffing costs.
System types
There is a range of integrated firefighting service (FFS) systems to choose from, and they can vary in design according to national standards.
Older-style jet foam or water monitor systems, such as fixed monitor systems (FMS), incorporate oscillating foam-dispensing monitors, and have to be manually operated and aimed. The newer DIFFS typically consists of a series of ‘pop-up’ nozzles with ‘both a horizontal and vertical component’ designed to provide ‘an effective spray distribution of foam or water to the whole of the landing area’, and they are able to guarantee an automatic response with a firefighting agent that covers the whole helideck in seconds, UK Civil Aviation Authority (CAA) documentation explains. Although FMS is an acceptable means of CAA compliance, authorities such as the CAA recommend hospital heliport operators make use of the newer DIFFS to deal with hazards such as post-crash fire on an elevated helipad.
Helipad firm Bayards Aluminium Constructions works with a third-party manufacturer that supplies firefighting systems to install DIFFS. Carlo Padoa, product manager helidecks at Bayards, explains how they work: “In case a fire is detected, our system can be activated via push buttons on the main control panel or the local push buttons at access points. The pump then starts feeding the water through the foam skid. Thanks to an inductor, the foam is mixed with water before reaching the helipad surface; it is distributed through several pop-up nozzles distributed around the helipad area in order to cover it completely.
The Dutch manufacturer, which has constructed over 600 aluminium helipads worldwide, is behind KHC’s new helipad and DIFFS. Now, in case of a rooftop fire, KCH is able to rely on a three-per-cent foam or water mix ‘within seconds across the entire 25-m [82-ft] square deck’. This will be ‘out of a water storage facility of 20,000 l [4,400 gallons] and a 600-l [130-gallon] foam tank, delivering the mix for at least five minutes, up to a height of three metres [10 ft], said Ian Taylor, head of security and local security management specialist CEF Directorate at King’s College Hospital NHS Foundation Trust.
“our system can be activated via push buttons on the main control panel or the local push buttons at access points”
Thanks to this new technology, dedicated elevated heliport firefighting systems, whether DIFFS or FMS, should have a response time of not greater than 15 seconds after release, as recommended by CAA in Chapter 5 of CAP 1264 for integrated heliport firefighting facilities. As reported on Bayards’ website, tests on its own systems have shown that in most cases a fire is extinguished in less than 10 seconds, and the system at KHC is reported to guarantee to extinguish a blaze within eight seconds.
FEC Heliport’s DIFFS works in a similar way. Engineering manager Jeff Sterwerf explains: “They are activated via a manual pull station. Then, an electric solenoid valve is released on the skid and water flows into a bladder tank squeezing the bladder and injecting the foam concentrate into the passing water stream. Once mixed, the foam water solution is delivered to the helipad at a three-per-cent concentration.”
According to point 5.10 of CAA’s CAP 1264 (Standards for helicopter landing areas at hospitals, published February 2016), the number and lay out of nozzles must be ‘sufficient to provide an effective spray distribution of firefighting media over the entire Final Approach and Take-Off Area (FATO)’, with a ‘suitable overlap of the horizontal spray component from each nozzle, assuming calm wind conditions’. But DIFFS are even designed to help a hospital ensure that ‘protection for the range of weather conditions is prevalent at the heliport’, as is clarified in the CAA documentation. With hospital rooftops such as Kings College, positioned on top of the hospital’s 10-storey Ruskin Wing, that could prove to be particularly helpful in windy conditions.
Water vs foam
DIFFS can employ a mix of foam and water or water only. Whilst foam is recommended as the primary medium by authorities such as the CAA, there can be exceptions where ‘a passive fire-retarding system is used in lieu of a solid plate’, says Kevin Payne, policy specialist helidecks and heliports at the CAA, and the author of CAP 1264.
“AFFF (aqueous film forming foam) creates a thin film layer on top of the burning fuel, preventing oxygen from reaching the flame and suppressing it within seconds,” explains Jelle van den Oever, system engineer at Bayards. He says a system with a foam-mixing inductor requires more components, which makes them typically more expensive. Sterwerf comments that the difference in cost between a water system and a foam DIFFS is roughly $25,000. He adds: “Technically, there is not a lot of difference as both [foam and water-only DIFFS] require similar flow requirements.”
A hospital looking to get a DIFFS installed can, of course, opt for one as part of a complete new hospital rooftop helipad. For example, according to Aluminium Offshore, the ‘XE enhanced safety helideck’ that was built for Rockhampton Hospital in Australia by the Singapore-based manufacturer included a ‘passive fire-retarding system incorporated into its aluminium decking’.
aluminium helipads can normally be retrofitted with a DIFFS
Alternatively, a DIFFS can be retrofitted into an existing hospital roof pad, such as was the case at KCH in London. The Bayards’ aluminium helipad itself was installed in 2014, and two years later a DIFFS was integrated into it. Some of the changes in line with CAP 1264 involved the replacing of the previous fixed monitor system (FMS) with 25 pop-up DIFFS nozzles. Payne says: “At KCH, there was the challenge of providing an additional water storage tank to accommodate extra requirements for primary water media [mixed with foam] as the total requirement of water for foam rises significantly.” A bigger foam tank was also installed inside the firefighting container.
“in Australia, the DIFFS solution is now being applied as the standard for all new build rooftop heliports”
An integrated DIFFS, says Padoa from Bayards, is ‘easier to install’ with ‘reduced lead times for the conception and delivery’. Nonetheless, he also adds that retrofits are ‘usually very possible’, although they are ‘highly influenced by the material of which the helipad is constructed’. An aluminium helipad, for instance, normally allows for an easier retrofit than a concrete one, which may present difficulties. “Another important factor for rooftop helipads is the accessibility of the bottom surface of the helipad to install the nozzles and the branch pipes of the fire water,” Padoa further explains.
There are a variety of practical and financial benefits for a hospital that incorporates DIFFS into its helipad. Stewerf lists ease of use, instant operation with complete coverage and increased safety, and financial benefits with fewer personnel required at each take-off and landing. In fact, Payne, who has witnessed the wide use of DIFFS on helidecks in the offshore environment since the early 1990s with ‘many hundreds of installations worldwide’, said that CAP 1264 was published because the CAA ‘was keen to introduce this tried and tested best practice from the offshore sector into the onshore environment’. He adds: “In Australia, the DIFFS solution is now being applied as the standard for all new-build rooftop heliports.”
According to Bayard’s van den Oever, DIFFS is more effective than, for example, the older monitor water-jet systems, as the latter needed ‘firemen or helipad operators to manually operate the monitors and direct the water jet in the right spot’, with ‘fire blazing and possible parts of crashing helicopters flying around’.
Aluminium Offshore’s website also points out that DIFFS, being automatic, allows ‘less chance of human error in traumatic situations’, and that the multiple nozzles are ‘less affected by blockages caused by debris’.
Taylor says a DIFFS solution was chosen for KCH as it was considered a safer operating system compared to its FMS predecessor: “Not having a firefighting team having to get on to the deck or to stay at their stations to fight a fire is a plus, as all the competent person is required to do in the event of a major fire is activate the DIFFS and retreat to a place of safety.”
Considering the cost of a DIFFS set-up, FEC Heliports gives an example of a foam system, including all piping and electrical work, that would cost a hospital approximately $100,000 to $150,000. But, says Padoa: “Overall, the costs for personnel and for their training are dramatically reduced, and the savings in terms of operational expenses positively tip the scales.”
“we are seeking to influence the international standards and recommended practices in ICAO Annex 14 Volume II”
Finance was a strong factor at KCH. Robert Bertram, CEO of helipad fundraising charity HELP Appeal, which donated £2.75 million ‘in part to fund the amount required to integrate the DIFF system into the helipad’, says: “[The new] state-of-the-art system will save the trust approximately £200,000 each year, compared to employing firefighters, providing a safe and efficient method in the event of a fire.”
Going forward
According to Payne, some hospitals building helipads in the UK are currently looking at both DIFFS and FMS, and he says: “With the publication of CAP 1264, [the] CAA is positively encouraging the use of DIFFS on rooftops.” He also adds: “We are seeking to influence the international standards and recommended practices in ICAO Annex 14 Volume II, which is reviewing the critical area calculation assumptions for heliports, in particularl on rooftops.”
For Bertram, the benefits of a DIFFS for hospitals are clear: “Going forward, should more DIFF systems be installed, they will be beneficial to a number of hospitals and major trauma centres across the UK, and King’s College is just the start of this process. They will help to ease the pressure on our emergency services, and ensure our hospitals are equipped to quickly and safely control a situation in the event of a fire, protecting all those within close proximity, and prevent further damage or evacuation to the rest of the hospital.”