Performance Specification Guide SD-15
EXAMPLE 4 - DESIGN REQUIREMENTS
Detail specifications often describe the product design by citing drawings and component specifications that must be followed. This leaves little room for the contractor to provide innovative designs or designs that reflect the latest technology. It also places a burden on the preparing activity to keep the specification and its referenced drawings and component specifications current, in order to reflect current industry practices. In detail specification
MIL-L-25370E, Valve, Pneumatic Inflator, (Life Preserver - M1-A), detailed design drawings are cited throughout the specification for each valve part. In the rewritten performance specification, MIL-PRF-25370F, Valve, Pneumatic Inflator, (Life Preserver - M1-A), the detailed design drawings were eliminated and replaced by operational requirements and
figures included in the performance specification that showed the interface alignments and dimensions. Both the detail military and revised performance specification can be viewed in their entirety on the ASSIST database at https://assist.daps.dla/quicksearch/.
MIL-L-25370E, Valve, Pneumatic Inflator, (Life Preserver - M1-A) |
MIL-PRF-25370F, Valve, Pneumatic Inflator, (Life Preserver - M1-A) |
3.5 Design and construction. The dimensions and the shape of the inflating assembly shall conform to figure 1. 3.5.1 Inflating assembly housing. The inflating assembly housing shall be high pressure die- cast aluminum and shall be anodized and treated with dichromate seal. The discharge mechanism shall consist of an external lever and an internal piercing pin and shall have a seal that will prevent leakage of life preserver cell pressure with the lever in any position. The inlet of the inflating assembly shall be threaded to accept a carbon dioxide cylinder conforming to MIL-C-25369. A lock shall be provided to retain the carbon-dioxide cylinder in the inlet. An outlet shall be provided to mount the inflating assembly on a life preserver cell. Passages shall be provided for conducting gas from the punctured carbon-dioxide cylinder to the outlet when the lever is actuated. 3.5.1.1 Piercing pin. The piercing pin shall be cadmium-plated, hardened steel, having a case depth of 0.010 inch. A spring shall be provided to retract the pin immediately from the opening of a punctured cylinder. 3.5.1.2 Lever. The liner shall be 1/8 inch thick |
3.6 Operation. The pneumatic inflator valve shall operate in world-wide environmental conditions expected to be encountered by aircrew personnel. The unit shall function easily by personnel wearing standard flight gear. 3.6.1 Inflator valve housing. The inflator valve shall consist of an actuator that shall be flush with the inflator valve housing in the unopened position. The actuator shall be secured in the unopened position. The inflator valve shall consist of a piercing mechanism that will retract immediately from the opening of the punctured cylinder, and have a seal that shall prevent leakage of the life preserver cell with the actuator in any position. The inlet of the inflator valve shall be threaded to accept a carbon dioxide cylinder conforming to MIL- PRF-25369. A locking mechanism shall be provided to retain the carbon dioxide cylinder in the inlet. An outlet shall be provided to mount the inflator valve on the life preserver cell valve stem as shown in figure 2. A passage shall be provided for conducting gas from the punctured carbon dioxide cylinder to the outlet when actuated. The outlet shall align with the hole in the side of the stem regardless of which side of the outlet is toward the base of the |
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