STEK modules explained: Module A, B, C, D and E — which do you need?

STEK is not a certificate with one simple checklist — it's built up from a base certificate (the Algemene Eisen) plus one or more modules that specify exactly which type of refrigeration work your company is qualified for. Many installation companies know that they hold STEK certification, but not exactly which modules they carry, or whether that still matches the work they do today. That's a risk: carrying out work outside the scope of your certificate can be flagged as a nonconformity at an audit, and it can mean that as a company you're not covered for the jobs you take on.

This article sets out the module structure: which module belongs to which type of work, how you combine them, and how you determine what your company needs.

How the module structure is built up

Every STEK company certificate rests on the same foundation: the STEK Algemene Eisen. That's the base — requirements for quality management, personnel, tools and administration that apply to every certified company, regardless of which type of refrigerant or installation you work on.

On top of that base, you choose one or more modules. Each module contains the technical content requirements for a specific field of work: the type of refrigerant, the type of installation, or the nature of the work (for example a legally mandated inspection instead of installation and maintenance work). Your company certificate states exactly which module(s) you carry — and therefore which work you're certified for.

For the full background on the company certificate itself, see The STEK quality mark — what it is, what it gets you and how to keep it.

The modules at a glance

• Module A — F-gases (stationary): the base module for most refrigeration companies. Covers work on stationary refrigeration, air conditioning and climate installations and heat pumps filled with F-gases. Virtually every company that installs and maintains regular refrigeration, air conditioning or heat pumps needs this module.
• Module A/Transport — F-gases mobile installations: the same F-gases scope, but for mobile applications — refrigeration installations for road transport, rail transport, container transport, cooling on ships and fishing vessels, and air conditioning in buses. A separate track from Module A stationary, because the installations, risks and working conditions differ.
• Module B — CO2: for companies that design, install, maintain or professionally work with CO2 (R-744) as a refrigerant. CO2 systems operate with different pressure and safety profiles than F-gas systems, hence the separate module.
• Module C — EPBD: covers the legally mandated periodic inspections of air conditioning and ventilation systems and heat pumps with a nominal capacity of 70 kW or more, including the reporting of those inspections. This is an inspection module, not an installation or maintenance module — you need it if you want to carry out and report these EPBD inspections yourself. Background on this inspection obligation is in Does the air conditioning inspection obligation still exist in the Netherlands?
• Module D — Heat pumps: focused on advice, system design, selection, installation and maintenance of heat pumps as a whole — not just the refrigerant circuit, but also system choice and advice. Relevant for companies that actively focus on the heat pump market, for example for customers applying for ISDE subsidy. See also Heat pump: is maintenance and a logbook mandatory?
• Module E — Flammable refrigerants: for work with flammable and natural refrigerants such as propane (R-290) and R-32, aligned with the revised NPR 7600. With the rise of these refrigerants — partly driven by the EU F-gas ban on high-GWP alternatives — this module is becoming relevant for more and more companies. See Natural refrigerants: R-290, R-744 and ammonia compared and GWP values of refrigerants: complete table + explanation

Which module(s) do you need?

That depends entirely on what your company actually carries out, not on what you once applied for. A few rules of thumb:

• Do you carry out regular maintenance and installation on refrigeration, climate and heat pump installations with F-gases? Then Module A is the base.
• Do you (also) work on refrigerated transport, ship cooling or air conditioning in vehicles? Then Module A/Transport is added on top — Module A stationary doesn't automatically cover that.
• Do you install or maintain CO2 installations? Then Module B is required alongside Module A.
• Do you carry out and report the statutory 70kW EPBD inspections yourself? Then you need Module C — without that module you're not allowed to certify these inspections yourself.
• Does your company actively position itself as a heat pump specialist, with advice and system design as a core activity? Then Module D is a logical addition to Module A.
• Are you (or your technicians) going to work with propane, R-32 or other flammable refrigerants? Then Module E is needed, alongside the base of Module A.

Work that falls outside the modules your company carries may in principle not be certified as STEK-certified work — even if your technician does hold a valid personal certificate. The company certificate and the personal certificate are two separate things; both need to be correct for the job you're carrying out.

Can you combine modules?

Yes, and that's exactly the idea behind the modular setup: you build your certificate to match your company's practice. Most companies with a broad range of work carry several modules at once, for example A plus D for a company that, alongside regular refrigeration work, also actively designs and installs heat pumps, or A plus E for a company switching to propane installations.

If you already hold a valid Module A certificate, extending with a module is generally more efficient than building a certificate from scratch, because the base (Algemene Eisen, quality system, personnel file) is already in place. The Certification Body then mainly assesses the additional technical requirements of the new module. Don't rely on this blindly without checking with your Certification Body (for example Kiwa or SGS) — the exact turnaround time and cost of a module extension differ per body and per situation, and we're not filling in those figures here without a hard source.

What does the auditor check per module?

At the annual or periodic check, the auditor assesses not only the Algemene Eisen, but also whether your company actually meets the technical requirements of each module on your certificate — and whether the work you carry out matches the modules you carry. A general walkthrough of what an auditor checks is in STEK audit: what does the auditor check during a participant inspection?

STEK versus BRL 100 — two separate tracks

STEK modules are about refrigerants and installation types; BRL 100 is a broader quality certificate for refrigeration business operations that stands separately alongside it. Both can be relevant, but they don't replace each other. The difference and the overlap are set out in STEK vs BRL 100 — what is the difference, and which one do you need?

Summary

The STEK module structure consists of a base certificate (Algemene Eisen) plus the modules A, A/Transport, B, C, D and E, each linked to a specific refrigerant, installation type or type of work. Which module(s) you need is determined by the work your company actually carries out — not the other way around. If you carry out work that falls outside your certified modules, you run a risk at audit and potentially in terms of liability. If in doubt: check your current certificate, compare it with your actual range of work, and ask your Certification Body whether a module extension is needed.