Objective
Development of a blast walling system lighter than existing systems with comparable capabilities to be applied as a separation wall on both existing and new offshore structures. The system should have blast as well as fire resistive capabilities.
Five typical topside structures were selected in phase 1. Vapour cloud explosions were simulated with the reactive CFD code REAGAS in order to be able to select design overpressure ratios for each type. A theoretical analysis of 11 alternative concepts for an aluminium panel and 10 alternatives for a glass fibre reinforced plastic panel performed to compare blast and fire resistant capabilities in combination with weight and costs in order to be able to select one of them for further development.
Overpressures in the order of 10 to 100 kPa were calculated for the various lay-outs, however it was not possible to derive reliable design overpressure levels for the various types of lay-outs. It was then decided to aim at a system that can withstand 100 kPa overpressure for panel dimensions of 2.5 by 2.5 square meter with a fire resistance comparable to a H120 rating. Based on the theoretical analysis it was concluded that a glass fibre reinforced plastic panel had the best potential to meet these requirements.
Six panels were designed which differentiate in composition and boundary conditions. A manufacturer was selected which provided us with six 1 by 1 square meter panels. Various tests have been performed on these panels comprising static loads, determination of natural frequencies, gas explosions with maximum overpressures of 2 bars, fire loads and drop weight loads. All panels passed the explosion tests without visual damage. The fire test appeared to be selective. Only one panel showed promising results with respect to meeting the H120 rating.
This one was chosen for further optimisation. Optimisation of the selected panel resulted in a further reduction in weight by omitting a steel frame in which the panel had to be mounted and an improved bonding between inner core and outer skin materials. Construction drawings were composed and an assignment was given to a manufacturer for the manufacturing of three 2.5 x 2.5 square meter panels. The panels were delivered in December 1994.
Due to several reasons, testing of the large scale test panels was postponed until 1996. The three panels were tested for their blast resistance. All three panels passed the test in which a gas explosion with an overpressure of 1 bar was generated. Two of the already tested panels were subjected to a fire in a furnace test. Both panels failed early in the test, so none of the two passed the test successfully.
With the fire tests on the panels the project came to an end. Presently we are discussing possibilities to improve the fire resistance. We think that it is technically possible as the cause of the early failure is known.
The project is partially successful as a lightweight panel has been developed capable of withstanding a 1 bar overpressure due to a gas explosion.
The work programme was divided into six phases. The work was carried out by TNO Prins Maurits Laboratory and SLP Engineering London.
1. Determine blast wall parameters
- review topsides layouts for a number of existing facilities
- catalogue the sizes and fire ratings of the blast walls
- select a number of representative blast walls and choose an associated
design accident involving release of hydrocarbons for each wall
- compute blast loading corresponding to these accidents
2. Preliminary design
- analyse structural response of the blast walling systems under
the blast loading determined in phase 1
- perform preliminary design of the blast walling system (at least 5 concepts
will be considered)
- select the most promising concept for further development
3. Small scale tests
- produce small scale test panels
- perform gas explosion tests and fire tests
4. Detailed design
- choose one of the alternatives tested in phase 3 for optimisation
- detailed engineering of the attachments, fixings and fittings
- produce drawings of the system
5. Proving trials
- design large scale test specimen (three panels)
- fabricate test panels and supply test facility
- perform tests, consisting of an initial explosion loading followed by
a fire test
6. Commercialisation
- take out a patent on the walling system
- negotiate licensing agreements with manufacturers
- produce publicity material
- arrange visits and presentation for the major operators and design contractors.
Programme(s)
Topic(s)
Call for proposal
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DEM - Demonstration contractsCoordinator
2280 AA RIJSWIJK
Netherlands