STEK audit: what does the auditor check during a participant inspection?

STEK-certified companies are not assessed once and then left alone. Every two years a periodic inspection follows, in which an auditor from the certification body (CI) visits to check whether you still meet the requirements. This article explains exactly what that inspection involves, who gets interviewed, which non-conformities count as "critical", and what the consequences are if you don't correct them in time.

Please note: the facts in this article are based on the STEK-Controlemethodiek and the STEK Algemene Eisen, both version 1 July 2021 — the most recent publicly published versions on stek.nl at the time of writing. STEK adjusts its requirements periodically; if in doubt, check the current version on stek.nl or ask your certification body for the latest status. More importantly: from 1 September 2026, the renewed STEK scheme — which integrates BRL 100 version 3.0 — is declared equivalent to BRL 100 by the Minister of Klimaat en Groene Groei, meaning a valid STEK company certificate automatically satisfies the BRL 100 requirement. For existing certificate holders the transition arrangement is not yet finalised; check with your CI whether the control methodology described above still applies unchanged.

Who carries out the inspection, and how often?

It is not STEK itself that assesses your company, but a certification body (CI) that is accredited for this by the Raad voor Accreditatie (RvA), for both ISO 17065 and the STEK scheme. STEK itself supervises those CIs: at least once a year an evaluation takes place, and STEK itself attends an inspection as an audit of the CI.

For your company as certificate holder, the following applies: after the initial certification audit (the first assessment), the CI then carries out a periodic inspection every 24 months, always around the point in the year at which the certificate was originally granted, with a margin of at most three months earlier or later. A STEK certificate is valid for two years and three months after the date of the last audit — those extra three months are the margin the CI has to schedule the next inspection.

In addition to the regular two-yearly cycle, an additional inspection can also follow. That happens if a government regulator (think of the ILT) reports to the CI that your company has probably committed a violation of statutory regulations that relates to your refrigeration work.

What happens during the company inspection?

The periodic inspection consists of a visit by the CI to your company. The auditor inspects:

• The business management system
• The work instructions and procedures
• Whether your documentation is still up to date (documentation is only reassessed if it has changed since the previous assessment)

In addition, the CI interviews personnel who carry out the work on a sample basis — this part applies specifically to STEK Module A (stationary F-gases) and Module A/Transport. During those interviews it is checked whether the personnel know the work instructions and procedures, and also actually apply them in practice. The auditor can, for example, ask about a recent project which steps a technician went through. Important: the CI itself determines, on a sample basis, which people are interviewed — your company is not allowed to influence that.

The entire inspection must be completed within eight weeks. That period is suspended for as long as you are working on corrective measures following a critical non-conformity; after those measures have been taken, the CI then has four weeks to carry out a reassessment and complete the inspection.

How many technicians and projects are looked at exactly?

For Module A and Module A/Transport, the sample size for interviews and project reviews is linked to the number of certified persons (employed plus hired-in certified self-employed workers) you worked with in the preceding year:

• 1 to 3 certified persons: 1 interview, 2 project reviews
• 4 to 9 certified persons: 2 interviews, 4 project reviews
• 10 or more certified persons: 3 interviews, 6 project reviews

The choice of personnel and the projects/processes that are reviewed (installation, maintenance, service, repair or decommissioning) is made on the basis of a random sample by the CI.

Installation checks: how many and when

Separately from the company inspection, the CI also carries out installation checks — on-site checks of installations actually carried out. The number depends on how many STEK technicians your company employs: companies with 1 to 20 technicians usually get 2 installation checks, companies with more than 20 technicians get 4. These checks are carried out within one month after the company inspection.

How much time does the audit take?

The minimum time spent (in inspection hours) depends on your company size and the chosen module(s), based on the Algemene Eisen combined with one technical module:

• 1-3 employees: 4 to 6 inspection hours, depending on the module
• 4-9 employees: 5 to 7 inspection hours
• 10-20 employees: 8 to 10 inspection hours
• More than 20 employees: 10 to 14 inspection hours

If you combine several modules at the same time (for example Module A and Module D), at least 2 inspection hours per additional module are added, provided they are registered and carried out simultaneously.

Critical versus non-critical non-conformities

This distinction determines how quickly you have to correct course and how severe the consequences are. A critical non-conformity includes, among other things:

• Not taking corrective measures after a previously identified non-critical non-conformity, within the period set by the CI
• Five or more non-critical non-conformities during one audit
• Structurally failing to keep the required records
• Structurally failing to maintain the quality system
• Structurally or incidentally failing to carry out measurements or checks, resulting in a health or environmental risk
• Personnel insufficiently trained or professionally competent for the work
• Having work carried out by persons without the legally required diplomas or personal certificates (unless under supervision as part of training)
• The absence of technical equipment that meets the requirements
• Structurally failing to carry out calibrations within the set periods
• Improper use or misuse of the STEK certification mark or logo
• Fraud

A non-critical non-conformity is, for example, the incidental (not structural) failure to keep records, incidentally failing to maintain the quality system, or incidentally failing to carry out calibrations. The distinction is therefore often: incidental versus structural, and risk versus no direct risk to the quality of the service.

What if you don't resolve a non-conformity in time?

At the initial certification audit the rule is simple: as long as a non-conformity has not been resolved, no certificate is granted.

At a periodic inspection it is more nuanced. For every non-conformity you have to carry out a root cause analysis and take corrective measures; the CI assesses that analysis and its implementation. If you do not resolve a non-critical non-conformity within the period set by the CI of six months, the CI still issues a critical non-conformity for it — which can only be lifted again after the underlying non-critical non-conformities have also been resolved.

With a critical non-conformity the clock is tighter: if you do not resolve it within the period set by the CI of three months, a written warning follows with a response period of two weeks. If you do not respond adequately to that, a one-month suspension of the STEK certificate follows. If you still have not responded adequately after that month has passed, withdrawal of the certificate follows. In the case of established fraud, the certificate is withdrawn immediately, without these intermediate steps.

During a suspension you may no longer offer or deliver services under the STEK certificate. After a suspension is lifted, the CI first carries out a reassessment to establish that you once again fully meet the requirements.

What else an auditor takes into account

Apart from the core procedure, the CI also assesses elements from the Algemene Eisen that are less visible on the shop floor, but do need to be on paper:

• A written management policy aimed at emission prevention, safety and sustainability
• An annual management review of the quality system (with 4 or more employees this must be recorded in writing)
• Staff consultation with personnel at least annually
• Internal quality monitoring of employee qualification, project evaluation/checking of work orders, calibration of measuring equipment, and the handling of complaints and non-conformities
• That installation work is not outsourced to companies without a STEK certificate and/or BRL 100 certificate
• In the area of safe working: an up-to-date RI&E, information and instruction, periodic workplace inspections, PPE and a record of accidents — unless you already hold a valid VCA certificate, in which case conformity on this point is assumed

For the calibration system, it's worth also taking a look at Calibration of measuring equipment BRL 100: everything you need to know — the calibration requirements are closely aligned, even though it's a different certification scheme.

How to prepare

• Make sure your records (work orders, refrigerant records, calibration certificates) are in order and complete — structurally missing records is immediately a critical non-conformity
• Check whether your documentation is still up to date since the last assessment; only changes are reassessed
• Prepare your technicians for a possible interview: they must be able to explain what they did on a recent project and why
• Actually carry out the annual management review and the annual staff consultation and record this, especially if you have 4 or more employees
• Check that all outsourced installation work is placed with STEK- or BRL 100-certified parties

Related

More background on the STEK certificate itself can be found in The STEK quality mark — what it is, what it gets you and how to keep it. Not sure whether you need STEK, BRL 100, or both? Read STEK vs BRL 100 — what is the difference, and which one do you need?. For the annual reporting obligation alongside the audit itself, see STEK annual report: when is the deadline?. And for the BRL 100 equivalent of this article: The BRL 100 annual check: what the auditor expects.