The B500 and the B456 are built on the same Amerex aluminum-valve ABC platform we've covered before — the same family that includes the B402, and the same wear-parts bin the Amerex Parts Book draws from for all of them. But where the B402-vs-B500 decision is two 5 lb units with different fire ratings in an identical cylinder, the B456-vs-B500 decision is a real size decision: 5 lb against 10 lb, in two different cylinders, with two different fire ratings and — a detail Amerex's own catalog makes easy to miss — two different mounting options.
The nameplates aren't close. The B500 is rated 2A:10B:C. The B456 is rated 4A:80B:C — double the Class A rating and eight times the Class B coverage of the B500, from a cylinder that's roughly twice the shipping weight. If the rating shorthand itself is unfamiliar, our guides to what fire extinguisher UL ratings actually mean and to sizing Class B protection from 40-B to 160-B unpack both numbers. What follows is what the two units share, what actually changes between them, and which one fits a given wall, vehicle, or floor plan.
The two spec sheets, side by side
| B500 | B456 | |
|---|---|---|
| UL rating | 2A:10B:C | 4A:80B:C |
| Capacity | 5 lb ABC dry chemical | 10 lb ABC dry chemical |
| Amerex item number | 15312 | 14967 |
| Valve assembly | 11823 aluminum | 11823 aluminum — same part |
| Gauge | 03103-P, 195 PSI | 03103-P — same part |
| Hose & horn assembly | 06215-P (.147 orifice) | 05564-P (.191 orifice) |
| Downtube | 06212 | 01519 |
| Discharge time | 14 seconds | 22 seconds |
| Initial discharge range | 12–18 ft | 15–21 ft |
| Operating pressure | 195 PSIG | 195 PSIG — same |
| Height × width × depth | 15.25 × 7.25 × 4.25 in | 20 × 7.75 × 5 in |
| Cylinder diameter | 4.25 in | 5 in |
| Shipping weight | 9.25 lb (9.5 lb as B500T) | 18 lb |
| Included bracket | 888, wall (818 vehicle bracket on the B500T) | 801, wall — no vehicle-bracket variant offered |
| Recharge chemical | Standard ABC — Charge 552 / 550 / 509 | Standard ABC — Charge 552 / 550 / 509 — same |
| Manufacturer's warranty | 6 years | 6 years — same |
Both are stored-pressure units with drawn-steel cylinders, anodized-aluminum valve construction, and, per Amerex's catalog, a −65°F to 120°F operating range (the service manual notes some units are labeled −40°F to 120°F — check the nameplate). Neither model draws the dedicated recharge charge the B402 does — both take the same generic ABC dry chemical charge as the rest of this platform, which the Parts Book lists with no model restriction.
What the extra 5 lb actually buys — and costs
The rating gap is the whole point of stepping up — which rating an occupancy requires, and how many extinguishers a given floor plan needs, is set by NFPA 10; consult NFPA 10 and your authority having jurisdiction for the exact requirement for your building. What Amerex's own numbers show is the cost side of that trade. The B456 ships at 18 lb against the B500's 9.25 lb — close to double the weight to lift off a bracket and hold through a discharge. It's also 20 in tall against the B500's 15.25 in, so it needs a taller clearance on the wall. And it takes longer to empty: 22 seconds against 14, though it also throws slightly farther, 15–21 ft against 12–18 ft.
None of that makes the B456 the "better" unit — it makes it a different tool for a different placement. A 5 lb extinguisher that anyone on staff can pull, aim, and control one-handed is worth more in some settings than the extra Class A and Class B margin a 10 lb unit carries. That trade is the actual decision here, not a spec-sheet error to resolve.
Same valve, different hose — what the parts book actually shares
Both units sit on the Amerex Parts Book's list for "5 - 20 lb. Dry Chemical (Hose & Horn) Aluminum Valve Models," alongside the B402, B443, A411, and — across agent lines — the Purple K B479 and A413. The valve assembly is identical: Amerex's own part description for 11823 reads "Standard Valve Assembly - 5, 5½, 6 & 10 lb. with Loop" — the B456's 10 lb capacity is written directly into the same part that serves the B500. The gauge (03103-P, 195 PSI), valve stem assembly (06092-P), spring (01074-P), collar O-ring (05241-P), ring pin (00160-P), lock wire seal (01387-P), lever & rivet (11825), and handle & rivet (11826, the 5–10 lb version) are the same part numbers on both models' lines.
Two lines on that same list pick a different part by model rather than by size class, and they're the two that touch discharge and internal geometry. The hose and horn assembly is 06215-P (.147 orifice) on the B500 and 05564-P (.191 orifice) on the B456. The downtube is 06212 on the B500 and 01519 on the B456. Everything else on the valve — body, gauge, stem, spring, seals, lever, handle — is one part number across both.
One valve platform, two different mounting decisions
The bracket line is where the two models genuinely diverge, and it's easy to read past on the catalog's summary chart. The B500 ships with the 888 wall bracket standard, and Amerex builds a B500T variant around the 818 vehicle bracket — the same dual wall-or-vehicle setup as its 5 lb platform-mate the B402. Its USCG-approved bracket options run 818, 821, and 861H, with 818S, 821, 821S, and 807 available beyond that, and it uses the 860 rubber-strap bracket.
The B456 ships with the 801 wall bracket only. Amerex doesn't list a B456T in this catalog's model lineup at all — unlike the B417T, B500(T), and B402(T) above it on the same chart, the 10 lb B456 has no factory vehicle-bracket variant. Its USCG-approved bracket options are 809 and 895, its broader optional-bracket list runs 808, 809, 846, 889, 889HB, and 895, and it takes the larger 862 rubber-strap bracket, matched to its 5 in. cylinder where the B500's 4.25 in. cylinder takes the 860. If a vehicle mount is a requirement, Amerex's own model lineup answers the question before the rating does — that capability sits on the B500 side of this platform, not the B456 side.
What this means when you own one
Both units run the same maintenance clock. NFPA 10, quoted in Amerex's service manual for stored pressure dry chemical extinguishers, calls for maintenance "at least once a year," a complete teardown "every six years," and a hydrostatic test of the cylinder "every 12 years" — the same schedule regardless of which of the two you own. And both carry Amerex's standing warning against substitute hardware: the Parts Book states that "Amerex replacement parts must be used" to protect the UL listing and warranty, and that using "generic, off-the-shelf or substitute parts" voids it. Because the valve, gauge, and most of the internal hardware are literally the same part number on both models, a shop running a mix of B500s and B456s is stocking against one short list of parts, not two — it's only the hose and horn assembly, the downtube, and the bracket that change with the model.
So which one do you buy?
Choose the B500 where 2A:10B:C meets the specification and the priorities are weight and footprint — vehicles and equipment cabs (with the B500T's vehicle bracket), break rooms, offices, and light-commercial spaces where a compact, easily handled 5 lb unit is the right tool.
Choose the B456 where the hazard or the specification calls for more Class A and Class B coverage per unit — commercial and industrial floors, warehouses, and shops where a fixed wall mount is the plan and the extra rating over a 2A:10B:C unit is the point. If the requirement calls for more Class B rating than the B500 offers but the footprint still has to stay at 5 lb, the 3A:40B:C B402 is the middle step between the two.
What we stock
The extinguishers — the B500 and the B456 themselves, their platform sibling the B402, and the full ABC dry chemical collection.
Shared platform parts — the 11823 valve assembly that fits both, and the 03103-P 195 PSI gauge both units share.
Outfitting a floor plan or a fleet and need help matching rating and bracket to the requirement — or pricing a mixed order of B500s and B456s? Send us the details and we'll come back with options, pricing, and lead time — request a quote.
Sources
UL ratings, item numbers, capacities, dimensions, cylinder diameters, shipping weights, discharge times, ranges, operating pressures, and bracket fitments are from the Amerex Portable Fire Extinguisher Catalog. Part numbers, part descriptions, and recharge charge assignments are taken from the Amerex Parts Book (P/N 27277), specifically its parts list for 5–20 lb dry chemical hose-and-horn aluminum valve models and its ABC dry chemical charges list. Maintenance intervals are quoted from Amerex Owner's Service Manual 05602 for stored pressure hand portable dry chemical extinguishers. Where a rating or part is critical to your application, confirm it against the extinguisher's own nameplate and Amerex's current documentation, and confirm hazard classification, extinguisher count, and spacing requirements with a qualified fire protection professional and your authority having jurisdiction under NFPA 10.
ShopAmerex.com is owned and operated by Centurion Holdings Group LLC, an independent authorized distributor of Amerex Corporation products. We sell equipment and factory OEM service parts — we do not perform inspection, service, hydrostatic testing or recharging.