DECK-INTEGRATED FIRE FIGHTING

Helideck Fire Fighting

We provide full helideck fire fighting and safety equipment in accordance with Civil Aviation and related Codes including DIFFS units or foam monitors, complementary media and rescue equipment.

OUR DEVELOPMENT

Deck Integrated Fire Fighting System (DIFFS)

We were pioneers in the advent of the DIFFS in the various Civil Aviation standards including UKCAA CAP437 and ICAO standards. It was our public fire tests carried out in 2004 and 2008 in the presence of UKCAA and ICAO observers, that led to its incorporation in these standards. It also showed the superiority of DIFFS over other forms of helipad fire fighting methods. All DIFFS development worldwide stems from these early tests and approvals.

OPERATION

How DIFFS works

We strongly recommend that the primary fire fighting system for a helideck should be a DIFF system (Deck Integrated Fire Fighting). A DIFFS unit consists of a skid which processes firewater inflow to output foam or water and which is piped to multiple nozzles which are installed flush with the helideck surface. In case of fire, these nozzles automatically telescope and spray water or foam evenly onto the deck. Non-telescoping nozzles are also possible.

The system overview below relates to a foam DIFFS unit; a water DIFFS unit is essentially similar but somewhat simpler in configuration/hardware.

The corrosion resistant spray nozzles are spaced evenly across the helideck and sit flush with its surface to provide an optimal and even coverage of the helideck surface. The nozzles do not present any trip hazard as they protrude only a few mm above deck.

Upon detection of a fire via the UV/IR flame detectors, or on manual activation, a foam-water mixture will be released through the deluge valve-foam inductor unit, through the firewater piping network and to the pop-up spray nozzles. The foam is inducted through a turbine foam proportioner which eliminates the need for a separate foam pump and also gives a much more stable and correctly proportioned foam supply throughout the discharge period. 3% AFFF is usual but a 1% solution can also be used.

XE Enhanced Safety™ Helideck fire tests

This model of helideck does not need foam or other extinguishing agents to deal with a fire on its surface and only water is sufficient to extinguish the residual fire vapour burn after the bulk of the fuel has been drained off. In recent tests on this helideck attended by representatives from UKCAA, ICAO, DNV, LRS, ABS, a 450l jet fuel fire was controlled [1] in the following times:

Purely passive basis, i.e with no intervention: under 11 seconds

Assisted by a water DIFFS spray : under 4 seconds

[1] “A fire is deemed to be under control (fire intensity reduced by 90%) at the point when it becomes possible for occupants of the helicopter to be effectively rescued by trained firefighters” (UKCAA)”

ENGINEERING ADVANTAGES

DIFFS offers substantial advantages over the traditional foam monitor units:

Crew freed for rescue

Safer: rescue crew can work concurrently with spray activation instead of being stuck behind monitors

Frees up rescue and fire fighting crew to help with helicopter evacuation

Automatic operation

Automatic: less chance of human error in traumatic situations

Multiple nozzles

More efficient fire suppression and not affected by wind

Multiple nozzles less affected by blockages caused by debris

Fire fighting platforms

Fire fighting platforms can be eliminated or reduced

WATER DIFFS

Water DIFFS has lower overall cost

Complies with ICAO regulations

Lower CAPEX and OPEX costs

Deck fires extinguished much faster, when used in conjunction with a passive safety deck

Less maintenance, no foam testing or replenishment needed

Foam not as effective on a safety deck due to holes, water more effective (ICAO para 6.2.4.6.4)

……there is also a practical consideration for this type of porous design in-so-far-as fuel is removed from the surface by numerous holes, so too is the primary extinguishing agent. Consequently, as it is not possible to form an effective foam blanket on a perforated surface, a significant benefit of using foam is nullified. A passive fire-retarding surface is best used with a system capable of providing primary extinguishing agent (water) in a dispersed pattern that can envelop a burning helicopter. The recommendation is for a combination solution: a passive fire-retarding surface incorporating a water-only DIFFS, delivering water at an application rate that is consistent with a Performance Level C foam.

ICAO Heliport Manual, Doc 9261, 5th Edition (2021), Part II — Onshore Heliports, paragraph 6.2.4.6.4, Note.

SPECIFICATIONS

Technical Information

Typical Design Standards

The entire system has been tested and approved in accordance with UKCAA CAP437. Live fire tests were also carried out in accordance with CAA standards and witnessed by Class and the system is fully approved for us on any helidecks following UKCAA or ICAO standards.

System Components

The foam DIFFS system consists of an electric operated deluge valve, pop up spray nozzles, remote manual stations, UV/IR flame detectors, deluge valve release panel, foam storage tank containing foam concentrate 1% or 3% AFFF and a turbine foam proportioner.

Activation

The unit is capable of being activated either manually (by way of the remote manual stations) or automatically (by way of UV/IR flame detectors). All units have multiple activation methods with the most common being automatic activation with remote, manual override buttons.

COMPLIANCE

Important changes to CAP 437

In the CAP437 7th edition, 2013, Ch 5 version, the UK CAA made some important changes to the chapter on fire fighting:

Para 2.10 considers a Deck Integrated Fire Fighting System (“DIFFS”) to be “a more efficient alternative” to a Fixed Monitor System (“FMS”).

Para 2.10 Note says that “… where a DIFFS is used in tandem with a passive fire-retarding system…” it is permitted to select a seawater-only DIFFS to deal with a residual fire burn”. Installations fitted with an XE Enhanced Safety helideck can now use a water spray DIFFS instead of foam. This allows cost, maintenance, and management savings and is also a greener solution.

Para 2.11 lays out the specifications for the DIFFS unit and asks for the DIFF system to be tested in actual fire tests to “demonstrate compliance with the performance specification to the satisfaction of the HCA or other appropriate authority”

Para 2.11 also asks for this compliance testing to include testing for blocked nozzles caused by a helicopter accident.

Para 5 confirms that unmanned installations would be best served by a passive fire retarding helideck as it “represents the best available fire-suppressing mechanism…”

The DIFFS system is designed to provide a safer and more efficient alternative to the current Fixed Monitor Systems (FMS) installed on helidecks.

ALSO SUPPLIED

Fire fighting and safety equipment

We provide full helideck fire fighting and safety equipment in accordance with Civil Aviation and related Codes including DIFFS units or foam monitors, complementary media and rescue equipment.

Foam Monitors

Complementary Media

Rescue Equipment

IN SERVICE