UK ADR module revision

ADR Class 4 Flammable Solids Study Guide

Compare the three Class 4 divisions and revise ignition, self-heating, water-reactive substances, temperature control, containment and emergency precautions.

Practise Class 4: Flammable Solids in the app Read the Class 4: Flammable Solids guide

80 app questions3 practice topics

Module overview

What is the Class 4: Flammable Solids module?

ADR Class 4 brings together three related but distinct divisions: flammable solids and related substances in 4.1, substances liable to spontaneous combustion in 4.2, and substances that emit flammable gas when they contact water in 4.3. The label and division are therefore essential. Treating every Class 4 load as an ordinary combustible solid can lead to the wrong response, especially where air, water, friction or temperature increases the hazard.

The module covers subsidiary hazards, containment, segregation, PPE and exposure, with particular attention to avoiding heat and ignition. Some temperature-controlled Class 4.1 substances use self-accelerating decomposition temperature and self-accelerating polymerisation temperature controls. Drivers need to understand the purpose of those controls, monitor the load as instructed and report any loss of control promptly.

Syllabus coverage

What you study in Class 4: Flammable Solids

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.

Divisions 4.1, 4.2 and 4.3

The different behaviour represented by flammable solids, spontaneous combustion and substances dangerous when wet, together with their labels and transport precautions.

Ignition and subsidiary hazards

Heat, friction and ignition sources, plus possible toxic, explosive or corrosive effects that can complicate a Class 4 incident.

Temperature-controlled loads

The driver’s duties when SADT or SAPT controls apply, including protecting the set temperature and recognising a loss of temperature control.

Segregation and containment

Keeping incompatible goods apart, protecting packages from damage or moisture and understanding why an apparently intuitive response such as applying water may be dangerous.

Exposure and PPE

Selecting protection for the known hazards, avoiding contamination and involving specialists when the substance or reaction is not safely controllable by the driver.

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 & Hazards	30	—
Temperature Control, SADT/SAPT & Ignition	25	—
Segregation, Containment, Exposure & PPE	25	—
Module total	80	—

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Qualification context

How this module fits an ADR route

Class 4 belongs to Group B with Classes 5 and 9. General routes combine Core and a method-of-carriage module with either the individual classes or Common Characteristics and the relevant group selection.

The exact response to a Class 4 release depends on the division and substance. Never infer that water, air exclusion or cooling is appropriate without the transport information and emergency guidance for the load.

Revision plan

How to study Class 4: Flammable Solids

1Make the division the first step in every Class 4 question before considering fire or spill action.
2Contrast self-heating with water-reactive behaviour so that the controls are not confused.
3Revise SADT and SAPT as control concepts linked to temperature-sensitive loads, not as isolated abbreviations.
4Use scenarios involving damaged packages, rain, heat and incompatible loads to apply containment and segregation.

Common questions

Class 4: Flammable Solids FAQs

What are the three ADR Class 4 divisions?

Division 4.1 covers flammable solids and related substances, 4.2 covers substances liable to spontaneous combustion, and 4.3 covers substances that emit flammable gases in contact with water.

Why can water be dangerous with some Class 4 loads?

Class 4.3 substances can react with water and release flammable gas. The correct action must come from the substance information and emergency instructions, not a general assumption about firefighting.

Is ADR Class 4 part of Group B?

Yes. Group B contains Classes 4, 5 and 9.

Revise Class 4: Flammable Solids in ADR Driver Pro

Continue with all 80 Class 4: Flammable Solids questions, flash cards, bookmarks and saved practice history in the app.