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New fracture immobilization materials—a fire hazard?
Injury, 14.263-264
263
Printedin GreatBritain
New fracture immobilization fire hazard?
materials-a
A. R. Green and G. E. Phillips Department of Trauma tic and Orthopaedic Surgery, Cardiff Ro yal Infirmary
Summary
The inflammability of various new materials for the immobilization of fractures was tested. All synthetic substances ignited when tested as block specimens, but were far less inflammable when casts were used. It is felt. however, that patients should be warned to keep such casts away from flames. THERE are a great many new materials which have recently appeared on the market to replace or complement plaster-of-Paris for the immobilization of fractures. The majority of materials are tested by the manufacturers but we found that the literature supplied by most firmsdid not include information on inflammability. In fact, in only one Company User Manual (Johnson & Johnson) could we find any reference to the fact that a material might ignite. In a recent review article, Hunt (1980) made mention of inflammability of casts after preparation. Goldberg (1980) has performed inflammability studies on three products only, and he concluded that although one product did ignite it was quickly extinguished, and there did not appear to be a safety hazard. It was felt that the various materials should be tested and this property investigated.
MATERIALS
AND
METHODS
Two samples each of thirteen different immobilization materials (T&e f) were made in the form of blocks IOcm square, made up in the thickness required for immobilization of a typical forearm fracture according to the manufacturers’ specifications. These blocks were allowed to set fully over several days so that they were completely dry. Each square in turn was held in
the flame of a conventional methylated spirit burner, and the time taken for ignition was measured. The characteristics of the material when heated were observed. Those squares that did ignite were extinguished by immersion in a bucket of cold water. A further similar experiment was carried out on empty forearm casts. again using the flame of a spirit burner. RESULTS
Initial testing of fabric squares showed quite conclusively (Table f) that all synthetic materials would ignite with ease, whereas those with a calcium sulphate base would not. Further testing with full forearm casts (Table If) showed a similar trend, but to a far lesser degree, only becoming scorched when heated in mid-cast. However. if heated at a weak point, for example at the base of the thumb, or where a cast had split into layers, then the cast would easily ignite.
DISCUSSION The risk of an elderly person stretching
across a lighted gas ring or coming too close to a flame when stoking a fire is quite high, especially when wearing a forearm cast. We have shown that all synthetic materials can be easily ignited. Two of them not only ignited, but melted, forming a very hot burning plastic film which could cause a severe full-thickness burn on the limb beneath. Furthermore, one of the materials (Plastazote), when immersed in cold water whilst ignitedwhich one would do instinctively in the event of fire-spat out hot plastic droplets.
Injury: the British Journal of Accident Surgery Vol. 1~/NO. 3
264
Tab/e /.
Results of testing samples of immobilization
Material
Constituents
lgnition time
polyethylene
5s
Plastazote
Foamed
Hexcelite Baycast Scotchcast Orthoplast G lassona Neofract Zoroc
Polycarprolactone Polyurethane polymer Fibreglass/polyurethane Transpolyisoprene rubber Fibreglass/cellulose acetate Expanded polyurethane Calcium sulphate Melamine formaldehyde Calcium sulphate Calcium sulphate/ formaldehyde resin Aluminosilicate glass/ acrylic polymer Calcium sulphate Lenocloth Calcium sulphate/ netelast
Cellona Cellamin Crystona Gypsona Orthoflex
5s
material
Characteristics
Melts, drips and spits on immersion in water Melts
5s
5s 5s 5s 2s NI
Burns with flame
NI NI NI NI NI
NI, Not inflammable.
Table Il. Results of testing
Plastazote Hexcelite Baycast Scotchcast Orthoplast G lassona Neofract Zoroc Cellona Cellamin Crystona Gypsona Orthoflex
full forearm
casts
Ignites in 5 s, melting, but extinguishes when shaken Ignites in 20 s, melting on to inside foam Ignites in 17 s mid-cast, and 5 s at edges Scorching in mid-cast, igniting only at edges Scorching in mid-cast, igniting only at edges Scorching only, cast could not be ignited Scorching of stocking cover, only igniting when bare edge held in flame Not inflammable Not inflammable Not inflammable Not inflammable Not inflammable Not inflammable
However, when the same tests were applied to the full casts, the same degree of inflammability
could not be reproduced unless the cast was burnt at its edge where the patient would normally feel the heat, or if the cast had worn or split into layers. Hence these casts do not seem
to constitute the exceptionally serious safety threat that we had initially envisaged. A draft of this paper was made available to all companies who market synthetic material. Inflammability studies have been conducted by each and the materials have been seen to reach British Safety Standards. All are in agreement that inflammability studies are difficult to perform and to relate to clinical conditions, and one firm is contemplating further more elaborate trials. None the less, we feel that orthopaedic units using these plaster substitutes should be made aware of this aspect. These casts may constitute a possible risk, albeit small, to the patient if he or she is unaware of the inherent danger, and it may be wise to incorporate into the routine plaster instructions a written warning to keep the cast away from naked flames.
REFERENCES
Goldberg L. A. (1980) Determination ofthe flammability of commercial splinting bandages. Pharma. J. 225, 528.
Hunt D. M. (1980) New materials for the immobilization of fractures. B. J. Hosp. Med. 24, 273.
263
Printedin GreatBritain
New fracture immobilization fire hazard?
materials-a
A. R. Green and G. E. Phillips Department of Trauma tic and Orthopaedic Surgery, Cardiff Ro yal Infirmary
Summary
The inflammability of various new materials for the immobilization of fractures was tested. All synthetic substances ignited when tested as block specimens, but were far less inflammable when casts were used. It is felt. however, that patients should be warned to keep such casts away from flames. THERE are a great many new materials which have recently appeared on the market to replace or complement plaster-of-Paris for the immobilization of fractures. The majority of materials are tested by the manufacturers but we found that the literature supplied by most firmsdid not include information on inflammability. In fact, in only one Company User Manual (Johnson & Johnson) could we find any reference to the fact that a material might ignite. In a recent review article, Hunt (1980) made mention of inflammability of casts after preparation. Goldberg (1980) has performed inflammability studies on three products only, and he concluded that although one product did ignite it was quickly extinguished, and there did not appear to be a safety hazard. It was felt that the various materials should be tested and this property investigated.
MATERIALS
AND
METHODS
Two samples each of thirteen different immobilization materials (T&e f) were made in the form of blocks IOcm square, made up in the thickness required for immobilization of a typical forearm fracture according to the manufacturers’ specifications. These blocks were allowed to set fully over several days so that they were completely dry. Each square in turn was held in
the flame of a conventional methylated spirit burner, and the time taken for ignition was measured. The characteristics of the material when heated were observed. Those squares that did ignite were extinguished by immersion in a bucket of cold water. A further similar experiment was carried out on empty forearm casts. again using the flame of a spirit burner. RESULTS
Initial testing of fabric squares showed quite conclusively (Table f) that all synthetic materials would ignite with ease, whereas those with a calcium sulphate base would not. Further testing with full forearm casts (Table If) showed a similar trend, but to a far lesser degree, only becoming scorched when heated in mid-cast. However. if heated at a weak point, for example at the base of the thumb, or where a cast had split into layers, then the cast would easily ignite.
DISCUSSION The risk of an elderly person stretching
across a lighted gas ring or coming too close to a flame when stoking a fire is quite high, especially when wearing a forearm cast. We have shown that all synthetic materials can be easily ignited. Two of them not only ignited, but melted, forming a very hot burning plastic film which could cause a severe full-thickness burn on the limb beneath. Furthermore, one of the materials (Plastazote), when immersed in cold water whilst ignitedwhich one would do instinctively in the event of fire-spat out hot plastic droplets.
Injury: the British Journal of Accident Surgery Vol. 1~/NO. 3
264
Tab/e /.
Results of testing samples of immobilization
Material
Constituents
lgnition time
polyethylene
5s
Plastazote
Foamed
Hexcelite Baycast Scotchcast Orthoplast G lassona Neofract Zoroc
Polycarprolactone Polyurethane polymer Fibreglass/polyurethane Transpolyisoprene rubber Fibreglass/cellulose acetate Expanded polyurethane Calcium sulphate Melamine formaldehyde Calcium sulphate Calcium sulphate/ formaldehyde resin Aluminosilicate glass/ acrylic polymer Calcium sulphate Lenocloth Calcium sulphate/ netelast
Cellona Cellamin Crystona Gypsona Orthoflex
5s
material
Characteristics
Melts, drips and spits on immersion in water Melts
5s
5s 5s 5s 2s NI
Burns with flame
NI NI NI NI NI
NI, Not inflammable.
Table Il. Results of testing
Plastazote Hexcelite Baycast Scotchcast Orthoplast G lassona Neofract Zoroc Cellona Cellamin Crystona Gypsona Orthoflex
full forearm
casts
Ignites in 5 s, melting, but extinguishes when shaken Ignites in 20 s, melting on to inside foam Ignites in 17 s mid-cast, and 5 s at edges Scorching in mid-cast, igniting only at edges Scorching in mid-cast, igniting only at edges Scorching only, cast could not be ignited Scorching of stocking cover, only igniting when bare edge held in flame Not inflammable Not inflammable Not inflammable Not inflammable Not inflammable Not inflammable
However, when the same tests were applied to the full casts, the same degree of inflammability
could not be reproduced unless the cast was burnt at its edge where the patient would normally feel the heat, or if the cast had worn or split into layers. Hence these casts do not seem
to constitute the exceptionally serious safety threat that we had initially envisaged. A draft of this paper was made available to all companies who market synthetic material. Inflammability studies have been conducted by each and the materials have been seen to reach British Safety Standards. All are in agreement that inflammability studies are difficult to perform and to relate to clinical conditions, and one firm is contemplating further more elaborate trials. None the less, we feel that orthopaedic units using these plaster substitutes should be made aware of this aspect. These casts may constitute a possible risk, albeit small, to the patient if he or she is unaware of the inherent danger, and it may be wise to incorporate into the routine plaster instructions a written warning to keep the cast away from naked flames.
REFERENCES
Goldberg L. A. (1980) Determination ofthe flammability of commercial splinting bandages. Pharma. J. 225, 528.
Hunt D. M. (1980) New materials for the immobilization of fractures. B. J. Hosp. Med. 24, 273.