What Happens When a Refrigerant Cylinder Is Filled — And the Records That Let a Buyer Trace It (TSG 23 / GB)
· QUZHOU HUAFU NEW REFRIGERATION MATERIAL CO., LTD.
A fill is a sequence of go/no-go checks, not a single action — and every check is meant to leave a record behind.
1. The fill starts before the pump
The first step of filling a liquefied-gas cylinder is a decision: may this cylinder be filled with this gas at all? That question is answered against a checklist — and a cylinder that fails any line is not filled more carefully, it is not filled.
| Pre-fill check | What it rules out |
|---|---|
| Cylinder is inside its test (requalification) period | An out-of-date vessel must not be filled |
| Permanent marks legible — water capacity (WC), tare weight (TW), test date, cylinder specification | A vessel whose capacity cannot be read cannot have its fill limit verified |
| Colour band and warning label match the gas | Cross-filling the wrong medium into a cylinder that is dedicated to one gas |
| No dents, bulging, fire damage or corrosion pitting at the base | Loss of wall thickness |
| Valve, neck thread and valve protection undamaged, with the correct outlet for the gas family | A leak path introduced at the valve rather than the body |
| Cylinder is not under vacuum and is not holding an unidentified medium | Contamination of the product with the previous contents |
| Cylinder type is permitted for that gas and is inside its service life | Filling a cylinder outside its design envelope |
China’s framework puts the filling operation itself under TSG 23-2021 (Gas Cylinder Safety Technical Regulation) and the filling station under GB/T 27550-2011, while cylinder handling is covered by GB/T 34525-2017. Cylinder colour identification and warning labels are separate standards (GB/T 7144-2016, GB/T 16804-2011) — which is why the colour band is a check and not decoration. In US practice the equivalent gate is 49 CFR 173.301; ADR states the same position in 4.1.4.1 (packing instruction P200).
⇒ The output of this step is a decision, not a measurement. The retest and requalification stamp is the line most often failed.
2. The fill itself is a weight
A liquefied gas is never filled to a level. The fill limit is set so that the cylinder does not become liquid-full at the warmest condition the applicable framework assumes, so the quantity that may go in is a mass — and the only quantity that can be checked afterwards, by anyone, is mass.
For comparison: the basis of that limit is not the same across frameworks: the Chinese filling rules work from the maximum service temperature marked on the cylinder; 49 CFR 173.304a states the limit as a filling density; ADR 4.1.4.1 (packing instruction P200) uses a filling ratio together with the test pressure. The three are not convertible into one another — the figure that applies is the one given by the cylinder’s own marking and by the standard in force for that route.
| Step | What is measured | Why it is the control |
|---|---|---|
| Tare | The empty weight, from the stamped TW or from the scale | It is the denominator of net contents |
| Fill | Product admitted by weight, not by gauge, level or time | The limit is a mass limit |
| Recheck | Gross weight, and net = gross − tare against the declared net contents | An overfill shows up as a weight before the cylinder leaves |
| Cut-off | A scale that alarms, or shuts off, on overfill | The check that does not depend on the operator noticing |
The physics behind the limit is set out separately: filling ratios and temperature compensation. The operational point is narrower — a cylinder filled by eye, or topped up because the level looked low, has not been filled to a specification.
3. After the valve closes
The fill ends with checks recorded per cylinder, not per batch:
- Leak test at the valve and neck — a cylinder can pass a weight check and still be leaking at the seat.
- Valve cap or plug fitted and the valve closed.
- Final weight recheck, so the number that goes onto the paperwork is the weight of the finished cylinder.
- Marking of net contents and the lot number, so the cylinder can be tied back to the fill and to the certificate issued for that fill.
4. The record: what turns a cylinder into a lot
A fill record is the document that answers “what is in this cylinder, and when was it filled” without opening it. In the frameworks above the record is part of the filling operation, not an optional extra. These are the fields a receiver actually uses:
| Field | Used by the receiver for |
|---|---|
| Cylinder serial number and cylinder specification | Matching this cylinder to its own test history |
| Gas / grade, and the producing batch | Traceability to the producing entity’s certificate |
| Net contents, with gross and tare shown | The net-weight check at receipt |
| Date of fill and the filling unit | Establishing when the fill happened |
| Lot or batch number | Linking cylinder → fill record → COA lot |
| Retest due date | The vessel’s own date, stated rather than discovered |
⇒ The commercial test is simple: ask for the fill record for the lot you were shipped. If the answer is a certificate quoting a “typical analysis” with no lot identifier, then nothing on paper ties your cylinders to that certificate.
5. Why the medium changes the procedure
Two distinctions matter before two fills are compared as if they were the same operation.
- Single substances versus blends. R410A and similar blends are defined mixtures. A cylinder is filled from a homogeneous source; selectively topping up one component is not a filling step, it is a way to make the cylinder something other than the product on its label.
- A1 versus A2L media. Safety group and transport class are two different rulers: ASHRAE 34 assigns the A1/A2L group for flammability in handling and system design, while the UN class is the hazard class for transport. They are assigned by different bodies and neither follows from the other:
| Substance | ASHRAE 34 group | UN class | UN number |
|---|---|---|---|
| R32 | A2L | 2.1 | UN 3252 |
| R134a | A1 | 2.2 | UN 3159 |
| R410A | A1 | 2.2 | UN 3163 or UN 1078 |
R410A has no dedicated UN number: both n.o.s. entries in the table above are used in practice, and which one applies is settled by the carrier and by the rules of the destination market. A2L media carry additional requirements around ignition control and ventilation during filling and storage. A supplier’s filling capability and its licensed scope are not the same thing — ask which media the filling licence actually names.
6. What a buyer can audit without visiting the site
| Ask for | It establishes |
|---|---|
| The fill record for the lot shipped | What is in the cylinder, and when it was filled |
| The COA whose lot number matches the fill record | That the certificate belongs to your lot |
| Cylinder marks: WC, TW, test date, UN number | That the vessel and the gas identity are stated on the goods |
| Declared net weight per cylinder | That the invoiced quantity is checkable by weighing |
What we can provide
Our licensed filling scope covers R22, R134a and R410A. What we can put in writing for a shipment is its filling documentation: the fill record for the lot, the cylinder’s test date and net contents, the COA lot number that the fill record carries, and the UN number and proper shipping name for the gas.
Contact us with: the gas, the cylinder type and net contents required, and the destination market.
Sources
- TSG 23-2021 — Gas Cylinder Safety Technical Regulation (SAMR, China) — cylinder and filling-operation requirements.
- GB/T 27550-2011 — Safety specification for filling stations of gas cylinders (SAMR/SAC, China).
- GB/T 34525-2017 — Safety rules for handling, loading and unloading, storing and using of cylinder (SAMR/SAC, China).
- GB/T 7144-2016 — Cylinder colour marks; GB/T 16804-2011 — Precautionary labels for gas cylinders (SAMR/SAC, China).
- 49 CFR 173.301 / 173.304a — US DOT cylinder qualification and filling limits (PHMSA / eCFR).
- ADR 4.1.4.1 (packing instruction P200) (UNECE) — filling conditions for compressed and liquefied gases.
- UN 1018 / UN 3159 / UN 3163 — the proper shipping names and classes used for chlorodifluoromethane (R22), 1,1,1,2-tetrafluoroethane (R134a) and liquefied gas n.o.s. refrigerant blends such as R410A, as listed in the dangerous-goods name tables (GB 12268-2025). R410A has no dedicated UN number: the same gas is documented either under UN 3163 (liquefied gas, n.o.s.) or under UN 1078 (refrigerant gas, n.o.s.), and which entry applies is set by the carrier and by the rules of the destination market.
Prepared by Quzhou Huafu New Refrigeration Material Co., Ltd — a warehousing and filling operation (storage and cylinder filling/repacking), not a manufacturer. The standards above are public frameworks; site-specific requirements, and the licence scope of any particular site, remain subject to local regulation.
Need current specs, quota status, or a mixed-load quote for What Happens When a Refrigerant Cylinder Is Filled — And the Records That Let a Buyer Trace It (TSG 23 / GB)? Contact tom@hufluor.com with your spec & destination port.