Gulfstream MRO Hangar – Farnborough Airport

Friday 24, July 2020

Gulfstream MRO Hangar – Farnborough Airport

Introduction & Project Story

We beat off some serious competition to win the contract to design and install the deluge and sprinkler system at Gulfstream’s first purpose-built MRO Hangar in the UK. Built upon the privately operated Farnborough Airport this highly specified and quality build replaced Gulfstream’s previously rented Hangar at Luton Airport. Gulfstream are primarily US based company who have slowly been spreading their wings throughout the rest of the world. The project was full of technical and practical challenges for all parties. The builder Volker Fitzpatrick had to contend with unusually wet weather throughout the build and surprising finds buried in the ground, which all led to early delays. Our install began within the Hangar space after a successful BIM co-ordination exercise which led to just one prefabricated sprinkler pipe being altered. Even more impressive not one leak was noted during the hydraulic testing of all 8 hangar deluge installations. Upon completion our Service Division provided a temporary 50m3 sprinkler tank and diesel fire pump rated @ 5500 L/min to flush all 8 deluge installations one at a time to check that all open nozzles were clear. The flushing was done over an impressive 5 days which was made all the more impressive by the kit, power and plan of action being organised just a few days prior.

The Customer Tower and Support first fix led to a long 4-week BIM co-ordination session, which by and large bore fruit upon the installation of all the services.

The huge concrete raft the water supplies sit on was cast in a lightening quick 1-week period, with the casting crew working around the clock in a bid to catch up lost time early in the project. Incredibly the huge tanks some 11m high were eventually wrapped up in a full steel and cladded enclosure (pictured) which formed part of the Airports planning requirements.

By early spring the progress made by all was catching up with the original programme, and the original June PC date looked possible again. Then come mid-March everything changed with the threat of Covid19. Unfortunately, A&F had to leave site upon the announcement of the UK lockdown. We needed time to evaluate the situation without putting our staff at risk. 3 weeks passed and we returned to continue our works that after the main contractors and A&F’s Covid 19 measures had been put in place. Other trades had decided to work on leaving our work behind for the first time in the project. The challenge from here on in was finishing a large 700 head 2nd fix including hydraulic testing in 4-week period. 

The foam concentrate testing was probably the biggest challenge we faced on this project. To control and contain the huge amount of flowing foam water which meant having only 3 minutes to get a foam sample was the challenge. We installed a manifold on the end of the deluge control valve manifold. The foam manifold had 6 no 65mm hose outlets to assimilate a pro rata high flow of 11,000 L/min to prove the 2 no 250mm diameter foam proportioners were mixing to the required 3%. An ultrasonic flow meter was temporarily fitted between proportioners and foam outlets and the 6 hoses were attached to two 30,000 Lt tankers laden with antifoam. The valves on the foam manifold were opened by two operatives until the flow stabilised and the meter reached the required flow. a sample was taken and analysed on site to which we’ve never been so happy to see a percentage result within the tolerances allowed.

The rest of the commissioning including a cause and effect session for all to witness the correct operation of deluge valve release panels was carried out over a 2-week period.          

How The Gulfstream Deluge System Works

The deluge system in the Hangar Space is operated by a smoke (1st Knock) and heat detection (2nd Knock) within one of the hangar deluge detection zones. The zones feature drop curtains which help channel the smoke and heat into each zone. Whichever installation is triggered by the detections, the deluge installations either side are also triggered at the same time.  The foam water released onto the floor separates the flames/ignition source from the fuel surface which is also cooled.  3 deluge installations operating at once caters for a fuel spill fire that could spread out quickly across the hangar floor. Additionally to this column sprayers operate to cool the primary steel columns.

The Challenges Faced

  • Fitting the eventual Water Supplies within the already designed and planning approved enclosure.
  • To meet the NFPA deluge requirements in the hangar but keep the system pressure low enough to suit all the pressure ratings of the equipment.
  • To safely bracket the deluge riser and trunk mains, to enable the system to function correctly when coping with the initial force of the 3 no 200mm deluge installations operating.
  • To initiate three deluge installations at once.
  • To commission a water foam system with a maximum flow of 33,000 ltrs a min.
  • Gulfstream switched insurers mid project, meaning the new insurers FM Global had a say in the end product.
  • Working through the Covid19 crisis and specific challenges it posed to the site operatives and supply chains.
  • To handover a system the client can test and use.

Project Features

  • The building will act as both the UK Gulfstream HQ and Gulfstream customers waiting lounge.
  • Hangar Space to house and fully maintain 13 no large cabin Gulfstream Private Jets, incorporating watertight underground maintenance pods beneath the hangar floor.
  • A very exclusive waiting lounge called “The flight deck” featuring a private kitchen, lounge chairs and lots of large TV’s
  • Deluge Protection incorporating column protection enhanced with Low Expansion AFFF Foam within the Hangar Space to NFPA409.
  • Wet Sprinklers designed to a NFPA / FM Hybrid specification within the Ground Floor, First Floor and Second Floor Support and plant Areas.
  • Wet Sprinklers to the Customer Tower and Office Spaces.
  • A 2 million litre capacity underground tank/s to capture a full deluge operation within the Hangar.
  • A sound dead wall divides the hangar space from both Support and Customer Tower.
  • The Contract featured a coordination to As built BIM design.

The Associated Fire Risks

  • Oil and Aviation fuel.
  • Associated aircraft maintenance equipment.
  • Storage areas contain low end flammables.

The Statistics

  • A 250 Day Duration.
  • 20,444 m2 of Space.
  • Space for 13 large cabin Gulfstream Jets
  • The Largest Gulfstream MRO Hangar outside of the US.
  • 1000 Open Deluge Heads.
  • 100 Open Column Nozzles.
  • 700 Ceiling Sprinklers.
  • 800 Exposed Sprinklers.
  • 8 no 200mm Deluge Installations operated via a 2 knock heat detection system and bespoke programmed release panels.
  • 2 no 150mm Wet Installations.
  • The deluge system is designed to operate 3 no installations simultaneously which generates a huge flow demand of 33,000 ltrs/min to feed up to 300 open heads in the hangar space!!
  • The deluge system is enhanced with AFFF Foam to which a 10,000 litre supply was installed. A further pre-piped 100 per cent reserve foam tank has also been installed!
  • The sprinkler water supply consists of a large pumphouse housing 4 no FM approved 2500usgm diesel pumps each rated at 134 psi (3 duty, 1 back up). The water storage tanks hold 2,178,000 litres of water between them!

The Outcome

A system install delivered on time regardless of all the issues faced throughout the project. A high quality install finished to a high standard that’s still easy to test and look after.