# Record a pressure test or evacuation

Source: https://help.mucka.ai/gas-certs/record-a-pressure-test-or-evacuation
Category: Certificates
Last updated: 2026-08-18

> The two pre-charge certificates for refrigerant pipework, the strength and tightness test and the evacuation record, done properly as the standard requires.

Before a system is charged, the pipework gets two pieces of paperwork: the pressure and tightness test, and the evacuation record. Both are one-off certificates you link from the commissioning certificate, and both are where warranty arguments get settled.

## The pressure and tightness test

These are **two different tests**, and the certificate keeps them separate because the standard does. The strength test proves the pipework holds pressure: Mucka computes the required test pressure from the system's maximum allowable pressure and the pipework category, and you record what you applied and how long it held. The tightness test proves it does not leak — and a pressure hold is not a tightness test, so the form never offers it as one. You record the detection method (an electronic detector, or a bubble solution on low-GWP gases — Mucka will not accept a bubble solution where the refrigerant needs better sensitivity), the instrument, and confirmation the joints were still uncovered when you tested them.

The test gas is oxygen-free nitrogen. That is printed on the certificate as a fact, not offered as a choice — never oxygen, never the refrigerant.

## The evacuation record

Proves moisture and non-condensables were pulled out before charging. Record the pump, the **micron gauge** (a manifold gauge cannot read this range), single or triple evacuation, the final vacuum, and the standing test with the pump isolated. Put the manufacturer's stated target on the record and make the pass or fail call against it — the target is theirs, and Mucka does not invent one. A photo of the gauge at the end of the standing test is the single most useful piece of evidence on the certificate.

## Starting either one

From the install job, or from [**Certificates**](/gas-certs) with **New certificate** and the **Air Con** tab. Both are one-off records: they raise no reminders, and they print with your F-Gas certification numbers.