No. "Simple" does not describe the steel, the welds or the test standard. It describes the regulatory procedure.
It is still a pressure vessel: still designed to a pressure-vessel code, still weld-tested, still hydrostatically tested, still certified. The only difference is that when construction, pressure, volume, temperature and medium all fall inside a defined envelope, the regulator accepts the inherent risk as low and removes a layer of administration.
Four parameters and one construction rule, all satisfied at the same time — not any one of them.
| Criterion | Requirement |
|---|---|
| Design pressure | ≤ 1.6 MPa（16 bar） |
| Volume | ≤ 1 m³（ nominal, not measured capacity） |
| Design temperature | −20 ℃ ～ 150 ℃ |
| Medium | air, N₂, CO₂, inert gas, lubricating or edible oil; non-flammable, non-toxic, non-corrosive |
| Construction | shell with flat or dished heads (torispherical excluded), or two dished heads; single wall |
Two receivers at 1.0 MPa and 500 L can land on opposite sides of the line: one carries nitrogen, the other oxygen; one has a jacket, the other does not.
No use registration — the vessel is connected and runs. Under current rules, no periodic in-service inspection cycle within its design life.
But removing procedure does not remove responsibility. Daily condensate draining, watching the gauge and relief valve each shift, and an annual self-check of shell and welds all remain with the owner. What is relaxed is administration, not safety.
Do the arithmetic across the line before deciding.
Take a receiver from 1 m³ to 1.2 m³ — 20 % more volume — and it moves from the simple tier back into full pressure-vessel territory: registration, periodic inspection, supervised manufacture, a thicker documentation pack. The tank may cost slightly more; the compliance cost is a different order of magnitude. The same applies going from 1.6 MPa to 2.0 MPa: it is not "a bit stronger", it reclassifies the vessel.
Building inside the envelope saves years of paperwork. Building as a full pressure vessel saves a second purchase when the plant expands. Both are rational — what is not rational is crossing the line without noticing.
No. "Simple pressure vessel" is a Chinese regulatory category; it does not travel with the goods.
The same tank sold into the EU is assessed under PED and CE marking; into the US under ASME, where U or UM stamping depends on volume and pressure; into Malaysia, through DOSH registration.
A concrete case: a 1,000 L receiver at 16 bar sits neatly inside the Chinese simple tier. The EU's own "simple pressure vessel" directive (SPVD) requires pressure × volume to stay at or below 10,000 bar·L — this one is 16,000 bar·L, so it is assessed under PED, not the simple-vessel directive. Simple in China is not simple abroad.
The judgement we make most often for customers is not "can it be built" but "which route does it need" — and then the drawing, the certificate and the document pack follow that route:
Up to 1 m³ and 1.6 MPa — carbon steel or stainless, built on the simple-vessel route; standard sizes usually ship within a few working days; vertical or horizontal, with G, Rp or NPT threads to match your pipework.
Above 1 m³ or above 1.6 MPa — built as a full pressure vessel, with drawings, material certificates and weld and test records supplied together, so you are not left to assemble the dossier yourself.
Export — certified to the destination market, on all three routes: CE, ASME and DOSH.
We have manufactured air receivers since 2013, across three plants and 25,000 m² of floor space, holding ASME-U, ASME-UM, CE and DOSH certification.
