The 2 types · side-by-side

Distributor-facing reading. Each row gives best-for, key trade-off, capacity, price band, and how many of SPC's tier slots carry an option at that product type.

Product type

Best for

Key trade-off

Typical capacity

Price band

Brands SPC carries

Discharge Check Valve One-way flow · compressor → receiver

The $100 part that protects the $25,000 air-end.Every compressor in the territory. Reciprocating compressors (prevents backflow that pushes oil up through the intake on shutdown) and rotary-screw compressors (prevents reverse-rotation events that destroy the air-end). Also at the receiver inlet on multi-compressor systems where one machine can backflow into another.

Temperature rating must match the dischargeReciprocating discharge runs 300–400°F and requires a hot-discharge valve (Conrader piloted to 400°F, in-line / in-tank to 450°F). A general-service 225°F valve on a reciprocating discharge fails from thermal degradation within months. Rotary-screw discharge at 180–210°F tolerates general-service ratings.

1/4" – 2" NPT typical · 20–60+ SCFM body sizes
standalone · combination (check + pilot + unloader) units

$ – $$

2 / 5 · Conrader + Kingston

Safety Relief Valve ASME Section VIII · code-mandatory on every pressure vessel

Non-discretionary. The line on every quote.Every air receiver, every aftercooler vessel, every compressor discharge ahead of a shutoff. Two positions: receiver-mounted (1/2"–3" NPT, larger SCFM rating, sized to vessel MAWP) and compressor-head/discharge-side (1/8"–3/8" NPT, smaller SCFM, set 10–25 PSI above compressor cut-out).

Code-spec or it's not a safety valveASME UV stamp + National Board number required on every valve quoted for a code vessel. Set pressure at or below MAWP; relieving capacity at or above the compressor's full SCFM. A non-ASME "lookalike" fails inspection, voids insurance, and is a five-figure-per-violation OSHA citation. Annual lift test + 3–5 year recertification cycle.

1/8" – 3" NPT · 100/125/150/175/200/250 PSI common
brass standard · stainless for wash-down/food

$ – $$

2 / 5 · Conrader + Kingston

Reading the brand bench column — the bar shows how many of SPC's tier slots (Industry Leader · Emerging · Economical · adjacent) carry an option at that product type. A narrow bench here is by design: safety-side valves are code-driven, not tier-shoppable. Conrader anchors the compressor-service-grade check valves (with hot-discharge ratings to 450°F) and the small-body compressor-head relief valves; Kingston anchors the receiver-mounted ASME relief and discharge-line check valves at the sizes a fabrication or service shop quotes from stock. There is no economical tier in this category — non-ASME valves are not a legal substitute.