HEAT AND SMOKE PROTECTIVE HOOD

Abstract: A hood (10) of non-thermoplastic polyimide material with a pad (24) which is air permeable but prevents the passage of smoke or noxious gases to the interior of the hood.

Description: HEAT AND SMOKE PROTECTIVE HOOD PTF * T,T) OF THE INVΗlHZOTiS This invention relates to a hood for wearing on the head for use in fire protection situations or when a person is to be evacuated from an are or a room where there is a fire or where there is smoke or noxious fTimes. PRIOR ART There have been many proposals for protective hoods and respiratory devices, often intended to enable the wearer to breathe, when the su__τo-undi_r_g atmosphere is noxious or toxic. British Patent No. 1 56 088 (MORRIS) discloses a welder's hood with an air filter. British Patent No. 1 587 121 discloses head¬ gear and a respirator for aircrew. British Patent No. 1 593 360 discloses a hood of plastics material having welded seams in a special arrangement. British Patent No. 1 395 ®SS discloses clothing to wear in an operating theatre. British Patent No. 1 35 82 discloses a stretchable hood, and British Patent No. 1 30 70 discloses a stretchable suit. British Patent No. 1 103 3 Q 0 discloses a filter arrangement for use to improve the ventilation of motor vehicles. British Patent 1 173 143 discloses a hood or a glove which is ole- ophobic and has a lining which includes activated charcoal. Other proposals have been made in British Patents Nos. 1 87 121, 1 3763 , 1 088 2 3, 896 345, 842 766, 482137, 357 773 and U.K. Published Application No. 2 024 6 . ^^tJREΛiT OMPI " British Patent No. 15 558 shows a respirator hood tightly fitting the head with a filter container rigidly connected to a mouthpiece. British Patent No. 1 6134 shows a protective hood for use with an air—exhaustjfig device also worn on the head. None of the numerous suggestions mentioned above are in any way suitable to be worn by members of the general public seeking to escape from a burning building e.g. a hotel or a burning vehicle, e.g. an aeroplane, train, or bus. It is an a-im of this invention to provide a hood of simple construction which can be. folded flat, which is comfortable to wear, and which when worn provides good protection against heat and against breathing smoke and noxious gases such as the products of combustion. SUMMARY OF THE IN7EHTI0N According to the present invention in its broadest aspect, there is provided a hood of non-thermoplastics polyimide material having an open- end wherein the head of the wearer may be inserted and having, located in its front wall, a pad which is air permeable but which prevents the passage to the interior of the hood of smoke and noxious gases. c:.:?ι PP..')<'i__KyπT) EM_BODI_^FINTS In a preferred embodiment of the invention, the hood is made from two superposed substantially rectangular sheets or of one sheet folded down one of its longer sides of KΔPTON plastics material, of approximately 1000th of an inch (25 micrometres) in thickness . In a specially preferred embodiment of the invention a pair of tapes are provided on the hood whereby it may be securely fastened to the head, and according to an advantageous feature of the invention the tapes are located in such a manner as to m_______mise the dead space within the hood when the tapes are fastened in a prescribed manner. For this purpose the tapes may be fastened one to each upper corner of the rectangular hood, and then each led down to pass through a loop which is secured to the face of the hood, there being one loop at each side inset about 6 or 7 centimetres from the nearer edge of the hood and disposed about 15 - 18 centimetres, preferably 16 - 17 centimetres, from the bottom or open end of the hood. KάPTON is a Trade Mark of Du Pont de Nemours International S.A. , and APT0N film may be obtained from this company, PP and R Films Division, CH1211 Geneva, Switzerland. Alternatively, the hood may be constructed including an- elastic or rubber strap having two ends each of which is secuxed to an upper region of the front wall of the hood in such a way that the strap extends substantially horizontal when the hood is worn normally by an erect person, and also including a pair of neck tapes, each of which has two ends one of which is secured to the hood and the other of which is free, these tapes being led around the hood and passed through one or more loops attached to the hood, the arrangement being such that the tapes can be pulled in opposite directions to tighten a lower region of the hood snugly around the neck of the wearer. 5 In a particularly preferred arrangement according to the invention, a filter pad is provided over a "window", i.e. -an aperture made in one of the superposed sheets of "KΔPTON" film. The filter pad may be a 4-layer pa "whic includes the ollowing layers laminated to one another:- 10 1. (Outer) a layer of spark-resistant and flame-resistant charcoal cloth. 2. A layer of microfine fibre for example polycarbonate fibre, as another example a microfine polypropylene fibre layer may be used. 3. A layer of charcoal cloth in which the carcoal is in activated ■ ^•5 fo__m and which in addition is impregnated with a copper salt and - with organic compounds to render this layer adsorbtive to hydrogen cyanide and to nitrogen oxides. 4. A porous open cell plastics foam layer which is pre erably loaded with a suitable amount or example 60 grammes per square metrss 20 of activated charcoal powder. As an alternative to using " ΔPTON" film, one may use any polyimide film having adequate heat radiation resistance and chemical resista e at elevated temperatures and, which preferably is not a thermosplastic material. SHORT DESCRIPTION OF THE DRAWINGS The invention will be better understood from the following illustrative description of one non-l.-miting example thereof, given with reference to the accompanying drs-wings in which:- Figure 1 is a front view of one exaπple of protective hood according to the invention; Figure 2 is a vertical cross-section on the line II-II of Figure 1; Figure 3 s a cross section through a four-layer filτer p-ad used n a hooά as shown in Figures 1 and 2; and Figure 4 shows diagrammatically an alternative example of hood according to the invention. DET^TΓ.ΠT. DESCRIPTION OF PREFERRED EMBODIMENTS The illustrated hood includes front and rear walls 10, 12 made of a polyimide film which is lame-resistant, infusible, non-peimeable to gases, resistant to heat radiation and not thermoplastic. The front and rear walls are substantially rectangular and are joined around two or three of their edges to foun a bag or hood which can be worn on the head. The hood may be made from a single rectangular sheet of film which is folded over and then secured together along two edges so producing a rectangular bag shape with one end constit¬ uting an open mouth into which the wearer inserts his head. Alternatively it may be made from two superposed sheets joined along three edges. The open edges indicated at 14 in Figure 1. The front wall 10 has a window cut therein, and over this window is placed a filter pad layer which in the preferred embodiment of the invention is as shown in Figure 3 &B& comprises a four--layer laminate. This filter pad layer is secuxed to the wall 10 by adhesive, by heat sealing, or by other convenient means. Also attached to the front wall 10 are two tape loops 16, 18 each of these being joined to the wall 10 by their end portions and having a central portion separated from the wall 10 so that a tape 20 or 22 as the case may be, can be passed through the resulting loops so formed. In wearing the hood, these tapes 20 and 22 are then tied by the user around his neck, so in substance closing off the lower opening 14 and also flattening the hood to conform " quite closely to the head of the wearer in order to reduce the free space within the hood within which dead air can accumulate. It has been found that this particular arrangement of tapes and loops is partic¬ ularly successful from this point of view as vell as making the hood very easy to put on and take off. Referring now to Figure 3 . one example of a filter pad 24 is shown in Figure 3- Alternative filters may be used. The outer layer 26 (Figure 3) is preferably commercially available charcoal cloth prior to activation of the charcoal. The next layer 28 is a layer of microfine fibres for this purpose polycarbonate or polypropylene fibres may be used. A particularly suitable layer is randomized polycarbonate fibre sold by the company Carl Freudenberg of West Germany. This layer forms a good filter for particulate materia in smoke. The third layer is preferably a charcoal cloth which has been subjected to a double impregnation in order to render it such tha it will absorb hydrogen cyanide gas and nitrogen oxides. The fourth layer is a porous open cell plastics foam which is loaded with a suita amount of activated charcoal powder. Polyurethane foam having sub¬ stantially 60 grammes per square metre of such powder may for example be used. Filter including these layers in combination is believed to give good protection against the products of combustion and so will provide good protection to a person who wears such a hood during, for example, escape from a burning building. Figure 4 illustrates in front view an alternative design of hood according to the invention, which is similar to that shown in Figures 1-3, except as regards the arrangement of tapes. The hood 30 illustrated in Figure 4 has an elastic or rubber strap 31 extending across the top of its front surface, secured to the hood at each end. When the hood is worn, this strap 31 is pulled dow (indicated dotted at 31a_) and hooked below the chin of the wearer (or in a retainer as described later) so diminishing the internal volume of the hood. Alternatively, the strap 31 may be held down by a retainer 34 fixed to the front surface of the hood. The retainer 34 may be such that the strap 31 must be stretched to reduce its diameter in orde that it can be hooked or clipped or otherwise retained in a suitable recess or formation (not shown) in the retainer 34. The hood also includes a neck tape encircling the lower part of the hood and held by retaining loops 32, 33 and 38. The two ends 36 and 37 of the tape are free and when the hood is donned, are pulled one by each hand of the wearer in order to fit the lower part of the hood snugly around the neck of the wearer. It will be- seen that there has been particularly described and illustrated a protective hood, particularly intended for use by members of the general public unexpectedly involved in an emergency, wh can easily be manufactured, which can be folded flat, and therefore easily transported, which is easy to apply and comfortable to wear, which is easy to remove, and which will provide good protection in an emergency situation.

Claims: CLAIMS 1. A protective hood of polyimide plastics material having an open end wherein the head of the wearer may be inserted and having, located in its front wall, a pad which is air permeable but which prevents the passage to the interior of the hood of smoke and noxious gases. 2. A hood according to claim 1 wherein the hood is made from two superposed substantially rectangular sheets of polyimide plastics material, each of approximately 1000th of an inch (25 micrometres) in thickness, said sheets being secured together around three of their four edges. 3- A hood according to claim 1 and made from one substantially rectangular sheet folded over to provide two superposed sheets which are then secured together along two of their edges, the rectangular sheet being substantially 1000th of an inch (25 micro¬ metres) in thickness. 4- A hood according to claim 1 including a pair of tapes, each of which is fastened at one end to a respective upper corner of the hood and is then led down to pass through a respective loop, said loops being fastened approximately 2/3 down the height of the hood when the hood is flat and each being spaced from the adjacent vertical edge of the hood by a distance of substantially 18 to 20 percent of the width of the hood when flat. 5- A hood according to claim 1 including an elastic or rubber strap having two ends each, of which is secured to an upper region of the front wall of the hood in such a way that the strap extends substantially horizontal when the hood is worn normally by an erect person, and also including a pair of neck tapes, each of which has two ends one of which is secured to the hood and the other of which is free, these tapes being led around the hood and passed through one or more loops attached to the hood, the arrangement being such that the tapes can be pulled in opposite directions to tighten a lower region of the hood snugly around the neck of the wearer. 6. A hood according to claim 1 wherein the pad is a laminated pad having at least the following 4 layers laminated together: (i) as an outer layer a layer of spark-resistant and flame- resistant charcoal cloth; (ii) a layer of microfine fibre; (iii) a layer of charcoal cloth the charcoal being in activated foi the cloth being impregnated with a copper salt and organic compounds whereby this layer Is absorptive to hydrogen cyanide and nitrogen oxides; and (iv) a porous open cell synthetic plastics foam layer. 7- A protective hood compris ng an opαa-ended envelope of polyimide material which is flame—resistant, infusible, non-permeable to gases, resistant to heat radiation -and non-thermoplastic, the envelope being made up of front and rear walls of said material and the open end being of dimensions such that a wearer can insert his head therein, one of the walls having a window aperture therein covered by an air-pem-eabl≤ laminate capable of filtering out the gases hydrogen cyanide and nitrogen oxides thereby preventing ingress of such gases to the hood while allowing the wearer to breathe, the hood also having neck tapes so arranged that upon tightening the tapes iriinimise the volume of dead air within the hood and cause the lower region of the hood to fit snugly around the neck of the wearer.

Inventors: DE LA PENA MICHAEL, SMALL CHARLES WOCKER
Applicants: PENA MICHAEL DE LA, SMALL CHARLES WOCKER, DE LA PENA MICHAEL
Application year: 1982
Main classification: A62B17
IPC codes: A42B1, A62B17