BS 8619:2020 pdf free download – Determination of the resistance to hydrocarbon pool fires of fire protection materials and systems for pressure vessels – Test method.
4 Principle
This method provides an indication of how vessels protected with fire protection materials, or systems, perform when exposed to pooi fires on solid surfaces. It simulates the thermal loads to a vessel engulfed in a large pool fire through the use of burners to create a flame capable of engulfing a vessel. The simulated liquid hydrocarbon pool fire achieves a heat flux to a cool surface of 90 kWm2 to 120 kWm2.
NOTE The literature suggests that heat flux to a cool surface in a large pool fire is 80% to 90% due to radiation and the remainder is by convection.
To ensure that suitable test conditions are achieved and maintained, it describes calibration tests to be performed prior to fire testing, sets permitted tolerances from the calibrated set-up, and delimits environmental conditions.
5 Apparatus
COMMENTARY ON CLAUSE 5
Test laboratories should be aware of the significant potential hazards involved in pressure vessels testing. Facilities intending to undertake tests in accordance with this document should be designed to be safe in the event of vessel failure.
Apparatus employed in the testing should consist of the following:
a) a specially designed burner system to subject the test specimen to the conditions specified in the calibration section;
b) propane storage capable offuelling the test for the required duration;
c) equipment to control and monitor the propane flow rate throughout the test; and
d) equipment to vent and purge the vessel after testing.
An example P&I diagram for a vessel testing facility is shown in Annex B.
5.1 Burner system
Liquid propane fuelled burners shall be used to simulate a pooi fire.
NOTE 1 Burners are used because they provide more control over the test conditions.
The burner system shall be designed so that the resulting heat flux has a radiation fraction greater than 75%.
NOTE 2 The burner system should produce a low momentum and luminous fire of sufficient thickness so that the resulting heat flux is predominantly by radiation.
Burners shall be designed to achieve total engulfment and uniformity of heating that shall be present on all four sides of the vessel. The maximum nozzle spacing shall be not greater than 500 mm.
The burner system shall be designed to receive equal mass flow rates of propane to two diametrically opposite locations at the ends of the vessel to ensure broadly symmetrical heating. The supply line length and fittings shall also be designed to ensure equal propane flow to the burner system and all supply lines. Cooling of the supply shall be provided as necessary to protect the burner supply for the duration of the test.
The burner system shall be designed to ensure stabilization of the flow rate and stabilization of the flame temperatures, as defined by DFTs in fil, which shall be achieved within 2 mm of the test commencing.