Turnout gears or firefighters' clothing are very important as they play a key role in time of firefighting. They not only protect the firefighters from adverse conditions but maintain standard thermal conditions inside the clothing. Besides, the turnout gears must have some other additional properties like water repellent, provision for easy donning and doffing, etc. The raw materials of the fabrics for turnout gears are made from high-performance technical fibers, and the engineering of the three layers of fabrics helps to maintain the necessary comfort parameters inside the turnout clothing. Nowadays, modern turnout gears have the ability to protect the wearer against chemical and biological hazards as fire accidents often commence with these hazards.
Turnout Gear
Turnout gears are also known as Bunker Gear. The terms are derived from the fact that the trousers and boots are traditionally kept by the firefighter's bunk at the fire station to be readily available for use. This clothing is usually referred to as 'Fire Kit' in the UK and Ireland. In Hong Kong, it is referred to as 'Incident Gear'.
There are several other related types of protective clothing worn by firefighters, which are not usually called turnout gear. They are Hazmat suit, Proximity suit, Wildland fire suppression, etc.
Turnout gears can refer, depending on the context, to just the trousers and boots, and jacket, or the entire combination of personal protective equipment and personal protective clothing.
Total cost for a basic firefighter's system is around $10,000.
Fabrication of Turnout Gear
According to NFPA (National Fire Protection Association) 1971 for USA and similar standards in other countries, all turnout clothing must have three components:
i) An outer shell,
ii) A moisture barrier, and
iii) A thermal liner.
The outer shell represents the first line of defense for the firefighter. Its main purpose is to provide flame, thermal, and abrasion resistance. Water shedding is also an important characteristic of outer shells, and they are treated with durable water-repellent finishes.
The moisture barrier is the second layer of the turnout gear system, consisting primarily of a barrier laminated to a fabric substrate. Moisture barriers allow perspiration vapor to escape and provide liquid penetration resistance.
The main function of the thermal liner is to minimize, to a safer level, the amount of heat transfer from the firefighting environment to the body of the firefighter. The thermal liner is the major contributor to the TPP (Thermal Protective Performance) rating of a turnout system.
4. Design and performance requirement of firefighters turnout gear according to NFPA 1971- 2013 Edition
Both design and performance are important for the turnout gears. The major design and performance requirement of firefighters' turnout gear according to NFPA (National Fire Protection Association) 1971- 2013 edition are discussed in the following section.
4.1 Standard design requirements of NFPA 1971- 2013 Edition.
According to NFPA 1971- Edition 2013, the major design requirements of firefighters' turnout gears are-
4.2 Standard Performance Requirements of NFPA1971- 2013 Edition
According to NFPA 1971- Edition 2013, the major performance requirements of firefighters' turnout gears are-
5. Fabrics and Sewing threads used in Turnout Gear
The general specifications of the outer shells are as following-
Most common fibres used for the outer shells are generally the blend of Nomex, Kevlar and Carbon or Kevlar and Nomex or Kevlar, Basofil and Nomex or Kevlar, Nomex and PBO or Kevlar and PBI or Technora and PBO or Zylon and Technora. These fibres in different blending properties may be used but the above mentioned blends are mostly used.
These fibres/ the blend of fibres are used either in 100% spun or in spun- filament combination form and the most common weaves employed are Ripstop weave, plain weave, twill weave and knit substrate with aluminium laminate.
The weight of used fabrics for the outer shell is mostly in the range of 7.0 to 7.8 OSY (Ounces per Square Yard).
General specifications of thermal liners are as following-
The facecloth used for the thermal liners are mostly produced of Nomex or Lenzing FR, Twaron and Nylon blend or Proprietary PBI blend. The fabric may be woven in plain, twill or box weave structure. The batting used with the facecloth is normally needle punched or spunlace nonwoven of Aramid, Reprocessed Aramid, Kevlar and Nomex blend or Aramid and PBI blend.
The total weight of the thermal liners is in the range of 6.8 to 8.0 OSY (Ounces per Square Yard).
General specifications of moisture barriers are as following-
The fabric substrate used is made from Nomex and Kevlar blend, Nomex IIIA or Nomex IIIA and PBI blend in woven and nonwoven form. If nonwoven substrate is used then they are either needle punched or spunlace. The film used with the fabrc substrate is made from Bi-component ePTFU/ FRPU.
Total weight for the moisture barrier layer is 4.7 to 5.5 OSY (Ounces per Square Yard).
Normally sewing threads from high performance technical fibers like Kevlar, Nomex etc. are used as sewing thread for the manufacturing of turnout gear.
6. Test methods of turnout gears
The test methods for measuring different functional properties of turnout gears are listed below-
Test Methods and Requirements for Measuring Flame Resistance
1. Garment materials (Outer shell, moisture barrier, thermal liner and other materials used in garment): FTM 191A, 5903.1
2. Hood and Wristlet materials: FTM 191A,5903.1
3. Gloves (Composite): FTM 191A, 5905.1 (Modified)
Test Methods and Requirements for Measuring Conductive Heat Resistance
1. Garments Composites (Shoulder and knee area only): ASTM F1060 (modified)
2. Thread (Garments, helmets, gloves, footwear): FMS 191A, 1534:
3. Gloves (Composite): ASTM F1060
Test Methods and Requirements for Measuring Water Absorption, Water Penetration, Liquid Penetration, and Viral Resistance
1. Garment: ASTM F1359
2. Garment materials (Moisture barrier): FTMS 191A, 5512
3. Moisture barrier seams for garment, gloves and footwear: ASTM F903
4. Moisture barrier seams for garment, gloves, footwear: ASTM F1671
Test Methods and Requirements for Measuring Total Heat Loss and Element Function
1. Garment composite: ASTM F1868
2. Gloves: Liner Retention, Dexterity test and Grip Test
Test Methods and Requirements for Measuring Physical Properties
1. Garment materials (Outer shell, moisture barrier, thermal barrier): ASTM D5733
2. Garment material (Outer shell): ASTM D5034
3. Garment material seams (Major A, major B, monor seams): ASTM D1683
4. Gloves (composite): ASTM F1790 and ASTM F1342
5. Gloves (Gauntlet or wristlet): ASTM D3787 ASTM F1790
6. Hoods and wristlets: ASTM D3787 and ASTM D3940
Test Methods and Requirements for Measuring Miscellaneous Properties
1. Garment materials (Outer shell, liquid barrier and liners): AATCC 135
2. Garment trim and Helmet trim: Retro reflectivity and fluorescence test
3. Product labels (Garments, gloves, footwear, helmets and hoods): Label legibility test
4. Hardware (Garments, gloves, footwear, helmets): ASTM B117
7. Expectation from a turnout gear
A turnout gear must protect from the adverse situation but should have higher moisture vapor permeability of moisture barrier. Ease in donning and doffing turnout gear is important, especially once it is wet. Gears should be lighter, thinner, less absorbent and more breathable and of course must be free from design faults.
8. Conclusion
Turnout gears help firefighters' to protect themselves from the tough situation of any fire accident. Not only the protection capability of the gear from flame is important but design, breathability, donning and doffing, absorbency etc. are important for better result. CB protective firefighters' turnout suit is the latest edition of turnout gear systems and provides protection about CB (Chemical and Biological) agents, and a range of TICs (Toxic Industrial Chemicals) and TIMs (Toxic Industrial Materials). The design and other issues should be solved to get best result from the turnout gears.
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