Type-approved cats and DPFs: what the law requires in Ireland

Replacement catalytic converters and DPFs are legally controlled parts in Ireland, as everywhere in the EU. If your vehicle was approved to the Euro 5 or Euro 6 emissions standard, a replacement catalytic converter, DPF or other pollution control device must be type approved for it¹. In practice that covers most cars and small vans first registered from 1 January 2011, and some registered earlier¹. This guide explains what type approval means, which vehicles the law covers and how to tell whether a part qualifies.

What type approval means

Type approval is certification by an approval authority that a replacement part meets the legal standard for the vehicles it is approved for. In Ireland the approval authority is the National Standards Authority of Ireland (NSAI), and the Road Safety Authority (RSA) is the market surveillance authority, which checks parts on the market². An approval does not have to come from Ireland: EU member states may not prohibit, restrict or impede the sale of components that comply with the EU type-approval rules³. For a replacement catalytic converter or DPF, the approval tests compare its emissions with the original part on the same vehicle, and cover its durability and its compatibility with the vehicle’s on-board diagnostics⁴.

An approval covers a list of specific vehicles, with their years of manufacture⁴. That matters more than people expect: parts for different vehicles, approved to different Euro levels, can share the same housing and pipework yet differ inside, in their approval and in how they perform. A part that can be made to fit is not necessarily approved, or legal, for your vehicle and its Euro level⁵.

What the law requires

Euro 5 and Euro 6 vehicles: for a new replacement pollution control device intended for a vehicle approved to Euro 5 or Euro 6, national authorities must prohibit its sale or installation unless it is of an approved type¹. Catalytic converters and particulate filters (DPFs and GPFs) are pollution control devices for this purpose⁴.
When Euro 5 started: it applied to new cars and the smallest vans registered from 1 January 2011 (a year later for larger vans), and new models had to meet it from 1 September 2009, which is why some Euro 5 vehicles were registered before 2011¹. Euro 6 followed for new registrations from 1 September 2015¹. See our Euro emissions standards guide.
Older vehicles: for vehicles approved to earlier standards, national authorities must likewise prohibit the sale or installation of a replacement pollution control device that is not approved, where approval rules for that kind of part already applied; parts for vehicles approved before those rules existed are exempt¹. For catalytic converters the rules date from 1998⁸. The EU approval rules for replacement particulate filters cover Euro 5 and Euro 6 vehicles⁴, so a replacement DPF for a Euro 4 or older diesel need not be approved. A vehicle’s type approval comes before its first registration, often by years: if you’re not sure where yours stands, ask us before you order.
Who is responsible: in Ireland it is an offence for a business to make available on the market a component that is subject to approval without that approval^2,3.
Penalties: on summary conviction, a class A fine or up to 6 months’ imprisonment, or both; on conviction on indictment, a fine of up to €100,000 or up to 12 months’ imprisonment, or both².

Whatever part is fitted, to a vehicle of any age, it has to keep the vehicle within its NCT limits. The NCT checks that the emission control system fitted by the manufacturer is present, complete, properly connected and not bypassed, and measures the exhaust⁶.

Separately, removing a DPF fails the NCT: a DPF that was fitted when the vehicle was made but is now missing is a major fault⁶.

How to tell whether a part is approved

The approval mark. A replacement catalytic converter or DPF approved for a Euro 5 or Euro 6 vehicle carries an approval mark: a lower-case “e” in a rectangle, followed by the distinguishing number of the member state that granted the approval (24 for Ireland, for example) and the approval number^4,7. Wherever possible, the mark should be visible once the part is fitted⁴.
The vehicle list. An approved part comes with the list of vehicles it is approved for, with their years of manufacture⁴. If yours is not on it, the part is not approved for your vehicle.
The certificate. If you are not sure, ask the seller or the manufacturer for a copy of the type-approval certificate.
In our range, approved parts have an H at the end of the part number (for homologated, the industry term for type approved) and are marked Type Approved on the product page (see BM Catalysts part numbers explained).

A note on “sports cats” and de-cat pipes

High-flow “sports” catalytic converters and de-cat pipes sold “for off-road use” are generally not type approved for road vehicles. At the NCT, on a petrol vehicle, an emission control system fitted by the manufacturer that is absent, modified or obviously defective is a major fault, and so is an exhaust system that has been bypassed or obviously unsafely modified; on a diesel, an emission control system that is absent, incomplete or obviously defective is a major fault too. Either way, the vehicle fails⁶.

Where our parts stand

The parts we sell are manufactured by BM Catalysts, Europe’s leading independent manufacturer of aftermarket “hot end” emissions parts. In our range today:

every catalytic converter, DPF and combined unit catalogued for a Euro 5 or Euro 6 vehicle is type approved;
every combined catalytic converter and DPF, catalytic converter and GPF and SCR and DPF unit is type approved;
the parts without an H are catalytic converters listed for Euro 1 and Euro 2 vehicles and for some imported vehicles, and DPFs for Euro 3 and Euro 4 diesels.

Each product page lists the vehicles, years and Euro level the part is catalogued for: check them against your vehicle’s own standard, using our Euro emissions standards guide. Browse type-approved catalytic converters or find your vehicle.

Sources

Regulation (EC) No 715/2007 (Euro 5 and Euro 6), Article 10 (dates) and Article 11(1) to (3) (replacement pollution control devices). eur-lex.europa.eu
European Union (Road Vehicles: Type-Approval and Market Surveillance) Regulations 2020 (S.I. No. 556 of 2020), regulations 4, 5 and 17. irishstatutebook.ie
Regulation (EU) 2018/858, Article 6(5) and Article 84(3)(b). eur-lex.europa.eu
Commission Regulation (EU) 2017/1151, Article 10 and Annex XIII (type approval of replacement pollution control devices, points 3 to 5). eur-lex.europa.eu
BM Catalysts, “The importance of Euro level compliance”. bmcats.com
Road Safety Authority, National Car Test (NCT) Manual 2023, version 5.1, sections 8.2.1.1 and 8.2.2.1 (exhaust emissions control equipment). ncts.ie
Commission Implementing Regulation (EU) 2020/683, Annex V, point 1.1 (distinguishing numbers: 24 for Ireland). eur-lex.europa.eu
Commission Directive 98/77/EC of 2 October 1998, Article 3: replacement catalytic converters. eur-lex.europa.eu

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