Apparel – Guard or protector – Penetration resistant
Reexamination Certificate
2001-06-04
2002-11-19
Calvert, John J. (Department: 3765)
Apparel
Guard or protector
Penetration resistant
C002S081000, C002S069000, C002S243100, C428S166000, C428S920000
Reexamination Certificate
active
06481015
ABSTRACT:
FIELD OF THE INVENTION
The subject of the present invention is a textile complex for the production of thermal protective garments. The complex involved here is intended to provide thermal protection against heat and flames, being used for the production of garments for firemen, but also, more generally, in other fields of activity where there is a risk of burns due to heat or flames.
DESCRIPTION OF THE RELATED ART
As they did quite some time ago, firemen in France wear a leather jacket fitted with a cotton or woolen inner lining for comfort. Such a jacket does not provide suitable internal thermal protection. In other countries, the jackets worn by firemen are based on a textile, either without a waterproof barrier, which results in a reduction in the thermal protection, or with a waterproof barrier impermeable to water vapor, which prevents the evaporation of transpiration and increases the problem of thermal stress. Thermal stress is a physiological phenomenon resulting from the rise in internal body temperature, occurring due to the effect of external factors such as a hot environment or due to the effect of great and prolonged effort. Thermal stress is manifested by a rise in the internal temperature of the body which can no longer thermally regulate itself, which in turn can lead to illnesses, or even fainting or a cardiac event. It is now known that when the body temperature exceeds the normal temperature by +1.5° C., the judgement and reaction faculties are impaired to the point of leading to accidents in dangerous environments. The latest study on the deaths of firemen in the USA gives only 8% of deaths by burning, 42% of deaths are due directly to thermal stress while the remaining 50% are accidents without any obvious cause but which specialists increasingly compare with stupid accidents due to judgement being impaired by thermal stress.
There is a European directive relating to personal protective equipment used especially by firemen. A jacket must meet a certain number of criteria, especially those relating to protection against radiant heat and protection against convective heat, must have good thermal stability in terms of the constituent materials, must fulfil pure non-flammability criteria and must have a high impermeability.
Furthermore, a jacket must allow an operator to be protected under extreme conditions of the accident type, especially by allowing him time to escape. Thus, it is in particular necessary to protect a fireman from the phenomenon of flashover. Flashover is a very rapid transition step in the development of an urban fire and occurs when gases and vapors present in a room reach a temperature of 500 to 600° C. and suddenly burst into flames. In a fraction of a second, the temperature rises from 500 to 1000° C., corresponding to an incident heat flux of about 40 kW/m
2
. It is necessary for an operator to be able to withstand this sudden temperature increase for long enough to allow him to move away from the heat source.
It is known how to produce a textile complex allowing these objectives to be achieved. Such a textile complex comprises an outer protective fabric made of a non-flammable material, for example based on aramid meta-aramid or polyamideimide fiber. This fabric incorporates thermal protection properties, provides mechanical strength in terms of abrasion and tear resistance, and has undergone a water-repellency treatment in order to make water and chemical liquids in general to run off it as beads. Behind this protective fabric is an impermeable but breathable membrane, generally attached to a textile surface giving it mechanical strength, letting through the water vapor resulting, for example, from the transpiration of the wearer, but not water in its liquid form. Furthermore, this membrane provides a windbreak effect, which contributes to the thermal insulation of the jacket by reducing the rate of penetration of the heat flux. Placed under the membrane is thermal insulation consisting of a three-dimensional knit, like that described in document EP 0 443 991, or of a felt capable of trapping air, as described in document EP 0 364 370. This thermal insulation is generally sewn onto an antisoil lining.
Such a jacket has the advantage of providing excellent thermal protection against an extremely high heat flux of 40 kW/m
2
, with efficiency which is very high, or indeed excessively high since, because of its high insulatability, it does not allow the user to be aware of heat with a heat flux of 0 to 1 kW/m
2
, corresponding to the normal working conditions for firemen, or to detect potential danger. The overprotected operator, under these conditions, may be led to take ill-considered risks owing to impairment of his perception of the heat flux. Such a jacket is also not very comfortable as it is thick and heavy, and it becomes laden with water, especially in the thermal insulation material, which can, in the event of a sudden temperature rise, result in this water vaporizing and possibly burning the operator.
Furthermore, when the jacket is wetted, after work in a wet environment, or after it is washed, the felt or knit absorbs a great deal of water, which requires a lengthy drying operation during which the jacket cannot be used.
FIGS. 1 and 2
show two graphs illustrating the behavior of various complexes intended for producing garments for firemen, taking account of the European Standard EN 469.
FIG. 1
illustrates the change in the heat transmission factor TF% which is the ratio of the heat flux that has passed through the product to the incident heat flux Q
0
. The incident heat flux is the heat flux generated by a heat source to which the sample is exposed.
FIG. 2
illustrates the change in the alerting time T.
12
as a function of the incident heat flux Q
0
. The alerting time is the time after which the wearer becomes painfully aware of the heat. It is sought to obtain a T.
12
of about 15 seconds for an incident flux of 40 kW/m
2
.
The various curves shown in
FIGS. 1 and 2
were obtained by taking measurements on the following products or complexes, using the method in the standard EN 366 as described in its draft revision CEN/TC162/WG2/N266 of27/01/97:
A=leather
B=leather+cotton lining
C=leather+wool lining
D=woven+membrane+90 g/m
2
nonwoven+120 g/m
2
lining
E=woven+membrane+220 g/m
2
knit+120 g/m
2
lining
F=woven+membrane+120 g/m
2
felt+120 g/m
2
lining.
As examples, the following products were used:
Woven: a woven of reference 4781 from DMC Tissus Techniques, 2/1 twill, 195 g/m
2
, made of Nomex® Delta TA from Dupont de Nemours, a mixture of 75% meta-aramid fibers, 23% para-aramid fibers and 2% anti-static fibers.
Membrane: Reference 89/55 from Proline, an impermeable but breathable microporous membrane made of fire-retardant polyurethane, about 40 g/m
2
, laminated to a Sontara® Nomex® SL type E-89 nonwoven, a mixture of meta-aramid and para-aramid, about 90 g/m
2
.
Lining: a woven of reference 4948 from DMC Tissus Techniques, cloth, 120 g/m
2
, made of Nomex®/Viscose FR, a mixture of 50% meta-aramid fibers and 50% bulk-fire-retardant viscose fibers.
Non-woven: Sontara® Nomex® SL Type E-89, a mixture of meta-aramid and para-aramid, about 90 g/m
2
.
Knit: a three-dimensional knit of reference AR220 from TTI, 220 g/m
2
, made of Nomex® T450, 100% meta-aramid.
Felt: a needle-punched felt from DUFLOT, 120 g/m
2
, made of Nomex®, 100% aramid.
These various curves summarize perfectly the advantages and disadvantages of the various known jackets given above.
SUMMARY OF THE INVENTION
The object of the invention is to provide a textile complex for producing garments, which is lightweight and comfortable, which, under the usual operating conditions (flux from 0 to about 1 kW/m
2
), transmits heat relatively well (corresponding to a high TF%) and rapidly alerts the operator to the presence of danger (corresponding to a low T.
12
) and which, under critical conditions, such as a heat flux resulting from a flashover phenomen
Calvert John J.
Cantor & Colburn LLP
Europrotect France SA
Muromoto, Jr. Robert
LandOfFree
Textile complex for making clothes for protection against heat does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Textile complex for making clothes for protection against heat, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Textile complex for making clothes for protection against heat will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2935157