Quick answer
Use a blast cabinet for parts that fit inside a sealed chamber; use a blast room when components are large, heavy or produced in continuous batches that need walk-in space and abrasive recovery.
When a cabinet is enough
Cabinets are ideal for brackets, castings, tools, valves and other parts that operators can handle through gloves. Suction cabinets suit lighter cleaning; pressure cabinets cut faster on tougher scale and paint.
They reclaim media, limit dust escape and need far less floor space than a room — the default choice for most job shops.
When you need a room
Rooms allow operators (or manipulators) to walk around large weldments, frames, tanks and structural assemblies. Recovery floors and dust collectors keep the process viable for daily production.
If you regularly blast parts that will not fit a cabinet door — or you run multiple operators — plan a room early rather than forcing open blasting indoors.
Hybrid approach
Many plants run both: a cabinet for small parts and a portable pot or room for oversized work. Start with the mix that matches 80% of your weekly jobs, then expand.