The Respirator,air Filtering, cataloged under National Stock Number 4240-01-251-9456, is classified within Federal Supply Class 4240 (Safety and Rescue Equipment) of the Fire Fighting, Rescue, and Safety Equipment group. Government technical data includes 10 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4240-01-251-9456 |
| Item Name | Respirator,air Filtering |
| FSC / FSG | 4240 / 42 — Safety and Rescue Equipment |
| Status | ACTIVE |
| Mask Filter Quantity | 2 |
| Filter Type | CARTRIDGE AND FILTER PAD |
| Mask Type | HALF FACEPIECE |
| Material Type | ELASTIC |
| Criticality Code Justification | FEAT |
| Adjustability | ADJUSTABLE |
| Exhaust Valve | INCLUDED |
| Head Harness | INCLUDED |
| Filter Replaceability | REPLACEABLE |
| Material | RUBBER SILICONE CLASS Q MASK |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | Possible hazard — SDS may be required (DLA HMIC P) |
| Criticality Code | Y |
| Reference | Meaning |
|---|---|
| 2100-99 | 3/9 Design control — primary reference Survivair Corp Sub of Comasec Inc |
NSN 4240-01-251-9456 is a Respirator,air Filtering, classified under FSC 4240, Safety and Rescue Equipment. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 4730-01-484-9187. Verify interchangeability with system specifications before substitution.
Key specifications for 4240-01-251-9456: Mask Filter Quantity: 2; Filter Type: CARTRIDGE AND FILTER PAD; Mask Type: HALF FACEPIECE; Material Type: ELASTIC. 10 specifications are documented in the U.S. Government catalog.
Possible hazard — SDS may be required (DLA HMIC P). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.