UK ADR module revision

ADR Class 5 Oxidisers and Organic Peroxides Guide

Understand how Class 5.1 oxidising substances and Class 5.2 organic peroxides intensify fire, react with other materials and require careful temperature control.

Practise Class 5: Oxidisers & Organic Peroxides in the app Read the Class 5: Oxidisers & Organic Peroxides guide

85 app questions3 practice topics

Module overview

What is the Class 5: Oxidisers & Organic Peroxides module?

ADR Class 5 is divided into 5.1 oxidising substances and 5.2 organic peroxides. Oxidisers may supply oxygen or otherwise support combustion, so they can intensify a fire even when atmospheric oxygen is limited. Organic peroxides combine combustible material and oxygen within the same substance and may decompose energetically, making contamination, heat and incompatible materials particularly important.

The module covers labels, subsidiary hazards, segregation, containment, exposure and PPE. Certain Class 5.2 loads require temperature control linked to the self-accelerating decomposition temperature. Drivers revise how to avoid overheating and ignition, preserve the required control conditions and escalate a problem before decomposition or package failure develops. Clean handling matters because contamination by incompatible material can disturb a substance and accelerate an otherwise controlled reaction.

Syllabus coverage

What you study in Class 5: Oxidisers & Organic Peroxides

These themes group the official learning objectives into practical revision areas. Open the topic map below for the exact question-bank structure used by ADR Driver Pro.

Class 5.1 and Class 5.2

The difference between oxidising substances and organic peroxides, their marks and labels, and the general precautions used for each division.

Oxidation and fire behaviour

How oxidation can support combustion without relying solely on air and why contact with combustible or incompatible materials can make an incident more severe.

Organic peroxide decomposition

The combined combustible and oxygen-containing nature of organic peroxides, their sensitivity to heat and contamination, and possible explosive, toxic or corrosive subsidiary hazards.

SADT and temperature control

The purpose of self-accelerating decomposition temperature controls and the driver’s duty to protect, monitor and report temperature-controlled loads.

Segregation, containment and PPE

Separating incompatible goods, preventing package damage, responding to exposure and protecting the eyes, skin and respiratory system from Class 5 hazards.

Practice-topic map

Question-bank coverage

The app total counts unique questions in each canonical practice topic. The free column is the separate TopicsLite.plist subset available on this website.

Practice topic	In app	Free online
Divisions, Marking & General Hazards	30	—
Oxidation, Organic Peroxides, SADT & Ignition	30	—
Segregation, Containment, Exposure & PPE	25	—
Module total	85	—

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Qualification context

How this module fits an ADR route

Class 5 belongs to Group B with Classes 4 and 9. It may be taken individually or as part of grouped training with Common Characteristics, Core and the chosen Packages or Tanks route.

Because oxidisers and organic peroxides behave differently, the division and substance information must lead any operational decision. The same generic fire response is not suitable for every Class 5 load.

Revision plan

How to study Class 5: Oxidisers & Organic Peroxides

1Separate “not necessarily combustible” from “can strongly support combustion” when revising Class 5.1.
2Connect Class 5.2 decomposition, contamination and heat instead of treating organic peroxides as ordinary flammable liquids.
3Use SADT scenarios to practise monitoring, temperature-control failure and early escalation.
4Pair segregation questions with realistic incompatible materials and package-contamination risks.

Common questions

Class 5: Oxidisers & Organic Peroxides FAQs

What is the difference between ADR Class 5.1 and 5.2?

Class 5.1 covers oxidising substances that can support or intensify combustion. Class 5.2 covers organic peroxides, which contain both combustible components and oxygen and may undergo self-accelerating decomposition.

What does SADT mean in Class 5 training?

SADT is the self-accelerating decomposition temperature. It is used to set temperature-control requirements for relevant organic peroxide loads.

Which ADR group contains Class 5?

Class 5 is part of Group B with Classes 4 and 9.

Revise Class 5: Oxidisers & Organic Peroxides in ADR Driver Pro

Continue with all 85 Class 5: Oxidisers & Organic Peroxides questions, flash cards, bookmarks and saved practice history in the app.