MIL-DTL-87174A(USAF)
2.4
Order of precedence. In the event of a conflict between the text of this document and the
references cited herein, the text of this document takes precedence. Nothing in this document,
however, supersedes applicable laws and regulations unless a specific exemption has been
obtained.
3.
REQUIREMENTS.
3.1
Qualification. The HGU-55/P helmets furnished under this specification shall be products
that are authorized by the qualifying activity for listing on the applicable qualified products list
before contract award (see 4.3 and 6.4).
3.2
Materials. The materials used in the fabrication and assembly of the helmet components
shall comply with the requirements of specifications referenced on the applicable drawings and as
specified herein.
3.2.1 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or
environmentally preferable materials should be used to the maximum extent possible, provided
that the materials meet or exceed the operational and maintenance requirements and promote
economically advantageous life cycle cost.
3.2.2 Shell. The shell shall be a fiberglass cloth and epoxy resin laminate in accordance with
MILP25421, Type I, Class 1, laminate cloth base number 181 or 181150. The shell shall be
comprised of 5 plies of reinforcing material that overlap at the centerline. The shell shall be a semi
voidfree laminate and shall contain no defects which exceed those defined under 3.6 of MILP
9400. The molded shell shall conform in shape, contour and thickness to 81D5332 for the size
medium; 81D5333 for the size large; and 81D5334 for the size extralarge. The thickness of the
shell shall be within a range of 0.035 to 0.050 inch, except that a maximum thickness of 0.095 inch
shall be permitted in the area of the laminate where reinforcing material is overlapped.
3.2.3 Fastener pile fabric. The fastener pile fabric used for earcup retention shall be in accordance
with Drawing 79B4695.
3.2.4 Edgeroll. The leather used in the edgeroll shall be sheepskin in accordance with KK-L-254,
Type A, Class 1, Subclass A. The foam core used in the edgeroll shall be polyurethane foam (see
6.8). The density shall be 3.5 to 5.0 pounds per cubic foot. The adhesive used in the installation of
the edgeroll shall be consistent with Class 2, 3, or 5, Neutral Form A or B of MIL-A5540 (see
6.8). The thread used in the installation of the edgeroll shall be unbleached or white color, and the
size and type consistent with AA52094.
3.2.5 Energy Absorbing Liner. The energy absorbing liner shall be fabricated from expandable
polystyrene plastic foam having a density of 2 - 2.5 pounds per cubic foot (see 6.8). The inner
surface (concave side) of the liner shall be coated with white shellac or water thinned white latex
coating which will not collapse, soften, or visibly affect the foam structure and which will form a
base for adhesion of the fastener tapes to the liner.
4
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business