Section 160.174-9 - Construction(a)General. Each thermal protective aid must be constructed primarily of a durable insulating or heat reflecting material that meets the thermal insulation requirements in § 160.174-11(a) . Each aid must be designed to cover the wearer's entire body, except for the area of the mouth, nose, and eyes.(b)Seams. Stitching, if used in structural seams of a thermal protective aid, must be lock type stitching that meets the requirements in Federal Standard No. 751 for one of the following:(1) Class 300 lockstitch.(2) Class 700 single thread lock stitch.(c)Seam strength. Each seam must have a strength of at least 225 Newtons (50 lb.).(d)Hardware. All hardware of a thermal protective aid must be of a size and design that allows ease of operation by the wearer. The hardware must be attached to the aid in a manner that allows the wearer to operate it easily and that prevents it from attaining a position in which it can be operated improperly.(e)Metal parts. Each metal part of a thermal protective aid must be-(1) 410 stainless steel or have salt water and salt air corrosion characteristics equal to or superior to 410 stainless steel; and(2) Galvanically compatible with each other metal part in contact with it.(f)Thermal protective aid exterior. The primary color of the exterior surface of each thermal protective aid must be vivid reddish orange (color number 34 of National Bureau of Standards Publication 440). The exterior surface of the aid must resist tearing when tested as prescribed in § 160.174-17(i) .(g)Hand and arm construction. The hand of each thermal protective aid must be a glove that allows sufficient dexterity for the wearer to close and open the zipper or other hardware of the aid and to open and eat survival rations, unless the glove is removable. The glove may not be removable unless it is attached to the arm and unless it can be secured to the arm or stowed in a pocket on the arm when not in use.(h)Retroreflective material. Each thermal protective aid must be fitted with at least 200 cm2 (31 sq. in.) of Type I retroreflective material that meets subpart 164.018 of this chapter.(i)Size. Each thermal protective aid must fit persons ranging in weight from 50 kg. (110 lbs.) to 150 kg. (330 lbs.) and in height from 1.5 m. (59 in.) to 1.9 m. (75 in.).(j)Lifejacket. Each thermal protective aid must be designed so that any Type I Personal Flotation Device meeting the requirements of this chapter can be worn inside the aid and, when worn, will not damage the aid and will not adversely affect its performance.