In Canada, we published an Advisory Circular back in 1997 directed at air operators outlining the recommendations for flight attendant attire but the recommendations are appropriate for all crew members. The document states, in part:
Background
Survival factors observations addressed in the Commission of Inquiry into the Air Ontario Crash at Dryden, Ontario included clothing worn by flight attendants. These observations are based on the investigation conducted by the human factors investigators, as reported by them in writing and in testimony before the Inquiry. In the Final Report, Justice Virgil P. Moshansky wrote "Another cabin safety issue involves the clothing worn by the flight attendants. Flight attendant Hartwick's outer clothing comprised slip-on shoes, a light dress, and a sleeveless vest. She lost one shoe in the aircraft and the other outside the aircraft, in the snow. She eventually borrowed a pair of shoes from a passenger, enabling her to better help the survivors. I see a need for there to be more attention paid to clothing all flight attendants in a manner that will allow them to better provide the leadership required of them in an emergency."
Safety experts agree that in order to decrease the chance of sustaining burns, it is better to wear long sleeves and pants than it is to wear short sleeves and short pants. In addition, natural fibres such as wool and cotton are better than synthetic fibres. Also, it is better to have enclosed low heeled shoes.
Fabrics:
* Research has shown that outer and inner garments made from natural fibres, such as wool and cotton, provide good protection as they do not flare up vigorously when brought into contact with an ignition source; they tend to self-extinguish once the ignition source has been removed; they char rather than shrink or melt; they do not transmit heat as readily as a synthetic material; and they are more resistant to destruction by radiant heat.
* Synthetic materials pose a hazard in a fire situation. Application of an ignition source will generally cause ready ignition of the material, and vigorous burning will continue when the ignition source is removed; transmitted or radiant heat will cause the material to shrink before it finally melts.
* Many synthetic fibres burn very easily and, when they burn, melt down very quickly, sticking to the skin.
Transport Canada - Air Carrier Advisory Circular 0136 ~ Flight Attendant Attire
Transport Canada - Cabin Safety Standards
In the US, there are also a number of published documents relating to uniform materials:
FAA Flight Standards Information Bulletin (FSAT) 97-01 (Appendix 3)
FSF Cabin Crew Safety ~ Uniform Materials Affect Flight Attendant Safety - Mar-Apr 99
NTSB Report AAR-96/03 - Uncontained Engine Failure/Fire ValuJet Airlines Flight 597
FAA Flight Standards Service ~ Cabin Safety Home Page