CEMA STANDARD (CEMA)

CEMA — the Conveyor Equipment Manufacturers Association, headquartered in the United States — is the dominant North American conveyor industry body and the publisher of the widely-cited 'Belt Conveyors for Bulk Materials' design manual, commonly known as the 'CEMA orange book' (now in its 7th edition, with extensive worked examples and electronic spreadsheets). The orange book covers belt sizing, idler class selection ([CEMA Class A–F](/glossary/cema-idler-class)), pulley diameter selection, take-up sizing, drive arrangement, chute design and dust control. It is the U.S. counterpart of [DIN 22101](/glossary/din-22101) and is referenced in tender specifications across the Americas, Asia and Africa.

CEMA also publishes a series of focused component standards. CEMA Standard 502 covers troughing and return idler dimensions and load ratings. CEMA 575 covers belt cleaners. CEMA 576 covers the conveyor pulley standard, replacing the older B105.1 series. CEMA 402 covers idler bearing seals. Many of these standards have aligned with — or been adopted into — international ISO documents (ISO 1537 for idlers, ISO 5048 for calculation method), but in practice CEMA remains the primary citation in North American projects, with ISO/DIN cited in parallel.

Engineers should note that CEMA and DIN can produce slightly different answers for the same duty because they use different friction-factor conventions, different safety-factor recommendations and different idler load-test methods. For multi-supplier projects it is normal to do both calculations and pick the more conservative result.