The Damper,flue, cataloged under National Stock Number 4520-01-551-3307, is classified within Federal Supply Class 4520 (Space and Water Heating Equipment) of the Plumbing, Heating, and Waste Disposal group. The manufacturer of record is Bird-Johnson Propeller Company, Llc. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Item Name | Damper,flue |
| FSC / FSG | 4520 — Space and Water Heating Equipment (FSG 45) |
| Manufacturers | Bird-Johnson Propeller Company, Llc (CAGE 07309) |
| Parameter | Value |
|---|---|
| NSN | 4520-01-551-3307 |
| Primary Part Number | H550380AB |
| Item Name | Damper,flue |
| FSC / FSG | 4520 / 45 — Space and Water Heating Equipment |
| Manufacturer | Bird-Johnson Propeller Company, Llc |
| Status | ACTIVE |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| H550380AB | Bird-Johnson Propeller Company, Llc (USA) |
| NM100179 ITEM 2 | Bird-Johnson Propeller Company, Llc (USA) |
| Reference | Meaning |
|---|---|
| 21537004-1 | 5/9 Secondary reference Mestek, Inc. Dba American Warming & Ventilating Division Div American Warming and Ventilating |
| 21537004-2 | 5/9 Secondary reference Mestek, Inc. Dba American Warming & Ventilating Division Div American Warming and Ventilating |
| VC-413-2167 | 3/9 Design control — primary reference Mestek, Inc. Dba American Warming & Ventilating Division Div American Warming and Ventilating |
NSN 4520-01-551-3307 is a Damper,flue, manufactured by Bird-Johnson Propeller Company, Llc, classified under FSC 4520, Space and Water Heating Equipment. Status: active.
NSN 4520-01-551-3307 has 2 manufacturer part numbers on file: H550380AB (Bird-Johnson Propeller Company, Llc), NM100179 ITEM 2 (Bird-Johnson Propeller Company, Llc).
No hazard code in the DLA record (HMIC N). 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.