Class E(g)(iii) light industrial: what actually qualifies

Class E(g)(iii) covers any industrial process that could be carried out in any residential area without harming the amenity of that area by reason of noise, vibration, smell, fumes, smoke, soot, ash, dust or grit. The test is about the process, not about where you want to put it. A quiet electronics assembly line qualifies whether it sits on a business park or behind a parade of shops. A spray booth does not qualify anywhere, even in the middle of an industrial estate, and it falls into Class B2 general industry instead.

The wording of the light industrial limb

The Town and Country Planning (Use Classes) Order 1987, as substantially amended in 2020, puts three things inside Class E(g): offices carrying out operational or administrative functions, research and development of products or processes, and any industrial process meeting the amenity test above.

Class B2 is then defined by exclusion. It covers any industrial process other than one falling within Class E(g)(iii). So the two classes have a hard boundary, and the boundary is drawn by the list of nine nuisance factors.

Read the list again, because it is narrower than most people assume. It does not include traffic generation, hours of operation, external storage, visual appearance, fire risk or the size of the operation. A process that is quiet, clean and odourless but generates 40 lorry movements a day is still within Class E(g)(iii) on the statutory wording, though the traffic may be a planning problem in its own right.

The residential area test and why it is hypothetical

This is where advisers most often go wrong. The question is whether the process could be carried out in any residential area without detriment to amenity, as a general characteristic of that type of process.

It is not a question about the actual site. A council cannot say that because the unit is in a residential street, the test is harder to meet, and it cannot say that because the unit is in a general industrial estate surrounded by heavy uses, the test is easier. The words "any residential area" set a single standard applied to the process wherever it happens to be.

The consequence is useful. If an occupier can show that identical processes are routinely carried on in units adjoining housing without complaint, that is directly relevant evidence. And if the process is only tolerable at this location because there are no neighbours, it is B2 and should be described as B2.

Processes that fall out into B2

There is no statutory list, and the assessment is fact-specific. But some patterns recur in practice.

Processes that generally sit outside the light industrial limb include spray painting and powder coating, metal fabrication involving cutting, grinding or hammering, plastics moulding with heat and fume emissions, rendering and food processing with strong odour, timber machining that produces significant dust, and any process with plant that runs continuously overnight at audible levels.

Processes that generally sit within it include electronic and instrument assembly, light mechanical assembly using hand tools and small bench machines, additive manufacturing, garment making, laboratory-scale production, packing and kitting, and repair of small goods.

Two categories sit outside both. A number of activities are sui generis and therefore in no class at all, including vehicle repair and servicing, scrap yards, and waste treatment. Moving into a sui generis use always needs permission, however quiet the operation is.

Evidence a council will ask for

Where the occupier needs to demonstrate that a process falls within Class E(g)(iii), the evidence pack is short but it has to be specific.

1. A written process description covering each stage, the raw materials, and what leaves the building as product, waste or emission.
2. A plant and equipment schedule with manufacturers' sound power data where it exists.
3. Proposed hours of operation, including any plant running outside those hours.
4. Extraction and filtration details where anything is vented, with discharge point locations and heights.
5. Waste streams and storage arrangements.
6. Delivery and collection movements by vehicle type.

Where a vent or flue is involved, a Ventilation and Extraction Statement does that work properly, and where plant noise is the issue the council will usually want an assessment using the BS 4142 method. The broader approach to assembling this material is set out in the guide to the evidence pack for a change of use application.

One practical note. Environmental health officers read these documents before planning officers reach a view, and they tend to ask about the worst case rather than the normal case. Describe the loudest half hour of the week, not the average.

Conditions that restrict process type

A permission for a use within Class E ordinarily allows movement to any other use in that class without further permission. Councils know this, and where they are uncomfortable they condition it.

Two common forms. A condition limiting the use to a light industrial use falling within Class E(g)(iii) and for no other purpose within Class E. And a condition tying the permission to a named process or to specified plant, hours and delivery times.

Both are lawful in principle where the tests for conditions in Planning Practice Guidance are met, and both restrict the flexibility that made Class E attractive. Check the planning history of any unit before taking a lease, because a 2021 permission with a tight process condition removes the Class E flexibility the letting particulars promised. The note on conditions restricting use class or occupier covers when these conditions can be challenged.

Moving from office to light industrial

A move from Class E(g)(i) offices to Class E(g)(iii) light industrial is a change within the same class, so it is not development and needs no planning permission, subject to any condition of the kind above.

Four things still need attention. The lease will very likely specify a permitted user and may not allow industrial activity. Floor loading in an office building is often inadequate for machinery, and mezzanine or plant installation may itself need building control approval. A material change of use engages the Building Regulations in its own right, particularly for fire safety and means of escape. And the rating assessment will change, which affects the bill from the following effective date.

There is a planning consequence further out too. Class MA of Part 3 of Schedule 2 to the GPDO 2015, which allows prior approval for a change from Class E to dwellinghouses, has qualifying conditions about prior use and vacancy. Changing the use within Class E resets nothing about the class, but it does change the facts a future Class MA application would rely on, so record dates.

Where a certificate of lawfulness helps

Because a change within Class E involves no application, there is no document proving it happened lawfully. That gap causes trouble at rent review, on assignment, at sale, and when a complaint prompts an enforcement enquiry three years later.

A certificate of lawfulness of proposed use or development under section 192 of the Town and Country Planning Act 1990 is the clean answer where the change has not yet happened. Apply with the process description and the evidence listed above, and the council either confirms the proposed use is lawful or explains why it considers the process falls into B2. Either outcome is better than finding out during an enforcement investigation.

Where the change has already occurred, a certificate of lawfulness of existing use under section 191 does the same job, on evidence of what has actually been carried on and since when.

Draft the process statement and the supporting planning narrative in minutes and send them for professional review before submission. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. See the full list of report types for the technical documents an environmental health officer may also want.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.