Submission to the Victorian Bushfires Royal Commission
RADIANT HEAT REFLECTING CAPE: BUSH FIRE PROTECTION SUIT
An article in The Australian, 22 May 2009 concerning the Black Saturday bushfires quoted a fire expert (Dr K Tolhurst) as follows:
“The radiated heat of the 100 m high flames was capable of killing people up to 400m away.”
The radiant heat load in the proximity of a bush fire can often exceed 50 kW/m2.
Exposure to high levels of radiant heat is one of the principal causes of fatality and severe burns of people caught in bush fires. Exposure can also severely limit the ability to protect homes, to cross open spaces or to survive in or escape from vehicles.
Conventional clothing absorbs radiant heat. As a result, although clothing provides some initial protection, it rapidly heats up as the clothing absorbs radiation and the wearer is soon enclosed in very hot clothing. The most efficient radiation shield is a polished metal reflector. An aluminum foil suit that covers most of the body will reflect 90% of the radiation and reduce the radiant heat load on an exposed person by a factor of 10. Thus, a person near a bush fire developing a radiant heat load of 50 kW/m2 will experience only 5 kW/m2 and their time of survival will be greatly increased. As the intense phase of severe bush fires usually passes within ten minutes a reduction in radiant heat load will save lives.
Solartran Pty Ltd has supplied to the Commission for assessment a low cost, radiant heat reflecting cape made from aluminum foil bonded to flame resistant (fire retardant) plastic fabric. The cape supplied to the commission is “ready to wear”. However, the cape is designed to be easily fabricated from an inexpensive kit of material using a pattern and set of instructions. (Appendix 1).
The cape is easy to get into, is large enough to fit a range of adult sizes, allows freedom of movement when operating outside and can be folded in on itself to provide a radiant shield for all parts of the body. Child size cape also available. The cape can be hung in a hallway or can be folded into a small package and stored in the glove box of a car.
The cape is designed for emergency use in situations where a person may be forced to traverse an area that is subject to a high radiation load. For example fighting spot fires around a house or traversing a clearing or roadway that is bordered with burning scrub or trees. . The cape should be used as an overcoat over conventional clothing and robust footwear.
The inner plastic lining is a flame retardant plastic. However when exposed to naked flames the inner plastic lining will melt where the flame contacts the plastic. On removal of the flame the plastic will not sustain burning. The outer aluminum foil layer will not ignite or burn
Note that the material of the cape is not insulating. It provides only a radiant heat reflecting function. It does not provide protection against direct contact with burning material or direct contact with flames. In particular the cape is not designed to provide protection in a situation where a person comes in direct contact with flames, as for example, when walking through burning scrub or grass.
The cape provides no protection against the inhalation of hot air, embers, smoke or toxic fumes.
A simple test of the radiant heat reflecting performance of the cape can be obtained by using the TEST ARMBAND. The test arm band is a short tube of the reflecting material that may be slid onto the forearm.
The basic test is to expose the bare arm or the arm with clothing at reasonably close proximity to a radiant source such as the element of a radiant stove or an infra red lamp or an open fire. Having assessed the time for radiant exposure to reach an uncomfortable level the test arm band is slipped over the bare arm or over the clothed arm and the test is repeated at the same reasonably close proximity to the radiant source. This provides a simple personal assessment of the effectiveness of the material of the cape as a radiation heat shield.
An ADULT SIZE CAPE KIT with materials, patterns and instructions is available from Solartran Pty Ltd, Brisbane.
Ph/Fax 61 7 3378 6586 www.solartran.com.au contact : Dr Ian Edmonds. firstname.lastname@example.org
CAPE KIT PATTERNS AND INSTRUCTIONS