Light industrial under E(g)(iii) and the amenity test

Light industrial use class E sits at limb E(g)(iii), and it carries a qualification that the other limbs do not. The industrial process must be one that can be carried out in any residential area without detriment to the amenity of that area. That wording is part of the definition of the class, so a process that fails it is not in Class E at all, whatever the tenant calls it and whatever the lease says.

What the light industrial limb covers

Class E(g) groups three uses that can be carried out in a residential area without detriment to amenity: offices, research and development of products or processes, and any industrial process. The limbs were carried over from the former B1(a), B1(b) and B1(c) when the Use Classes Order was rewritten in 2020.

Typical E(g)(iii) occupiers are a joinery workshop with dust extraction, a bicycle repair business, a small-batch food producer, an electronics assembler, a picture framer, a bespoke furniture maker. The common feature is a process contained within the building, using hand tools and small machines, with no significant external plant and no process emissions beyond what a filter or a local extraction unit deals with.

The qualification is tested against a notional residential area rather than the actual surroundings. A workshop on an industrial estate still has to be capable of operating in a residential street to fall within the limb. That is counter-intuitive and it is the point most commonly misread.

Moving between office and workshop

Because all three limbs sit in the same class, and indeed in the same class as shops, cafés, gyms, nurseries and clinics, movement between them is not development. Article 3 of the Use Classes Order and section 55(2)(f) of the Town and Country Planning Act 1990 do the work together.

So a landlord can let a first-floor office to a jewellery workshop without an application, provided the process does meet the amenity qualification. That flexibility is real and it is one of the more useful features of the 2020 changes for small commercial landlords.

Two things can remove it. An article 4 direction can withdraw permitted development rights and, in some areas, target changes out of particular uses. And a condition on an earlier permission restricting the unit to a named use survives the reorganisation of the classes. Conditions imposed before the 2020 changes that refer to former use classes continue to be read by reference to those old classes, so a unit limited by condition to B1(a) office use remains limited to offices until a section 73 application varies it.

Read the planning history before committing. Our note on the planning unit and how councils decide what they assess covers the related question of what area the council will treat as the unit in the first place.

Processes that fall outside the limb

Where a process cannot be carried on without detriment to residential amenity, the use is general industrial under Class B2 or sui generis, and a change to it from a Class E use is a material change of use needing permission.

The indicators councils use are familiar. Operations requiring an environmental permit under the Environmental Permitting Regulations 2016. Processes with a flue or stack discharging beyond the roofline. Spray booths, foundry work, heavy fabrication with impact noise, plastics extrusion, vehicle body repair and paint spraying. Deliveries by articulated vehicles. Operations running through the night.

None of these is determinative on its own. A single small CNC router in an acoustically treated room is a different proposition from six of them running two shifts. What matters is the character of the process as actually carried out, which is why intensification of an existing use can itself require permission, as our note on doing more of the same explains.

Noise, fumes and hours in practice

Environmental health officers assess industrial and commercial sound against BS 4142, which compares a rating level derived from the specific sound source with the background sound level at the nearest sensitive receptor. Tonal, impulsive or intermittent character attracts a penalty, which is why a bandsaw or a compressor can matter far more than its measured level alone suggests.

Where a change of occupier is proposed in a mixed street, a Noise Impact Assessment measuring background levels at night as well as by day is the document that settles arguments. Take measurements before the tenant signs, not after the first complaint.

Fumes and odour follow the same logic. A Ventilation and Extraction Statement setting out the extraction route, the filtration, the discharge height and the maintenance regime is proportionate for most small workshops, and it also gives the occupier something to point to if a complaint is made.

Hours are the control that does most of the work. Offering a restriction to daytime operation with no deliveries before 8am removes the objection that actually worries neighbours, and it costs a small workshop very little.

Conditions on earlier permissions that still bite

Industrial estates built in the 1980s and 1990s are full of permissions with conditions restricting units to specified uses, limiting hours, prohibiting external storage and controlling the use of yard areas. Those conditions run with the land.

Three checks before a letting. Pull the planning history for the unit and the estate. Read every condition on every permission, including reserved matters and later variations. And check whether the estate has an overarching permission with conditions that apply to all units, which is common where the estate was consented as a single scheme.

Where a condition blocks the letting, section 73 is the route, and the application should be supported by the noise and extraction evidence rather than by an assertion that circumstances have changed. Our note on self-storage use class and council requirements deals with a related classification problem on the same kind of estate.

The landlord's practical problem

A lease that permits any use within Class E is only as good as the tenant's process. A landlord who lets on that basis and then finds a spray booth installed has a planning breach on the title and a tenant with no incentive to fix it.

Deal with it in the lease. Specify the permitted use by reference to the process rather than the class, require the tenant to obtain any consent needed for plant or extraction, and reserve the right to inspect. Those three clauses cost nothing at grant and save an enforcement notice later.

Evidencing the existing process

If you are arguing that an existing use is lawful and within E(g)(iii), the evidence is about the process rather than the label.

Record the plant list with power ratings, the hours of operation, the number of staff, the vehicle movements by type and time, the waste streams and their collection frequency, and the extraction or filtration installed. Photographs of the workshop in operation help. So does a short measured noise survey at the boundary.

Illustrative example: a former print unit on the edge of a residential area is let to a furniture maker. The landlord commissions a background noise survey before the letting, adds an acoustic enclosure to the extraction fan, and offers hours of 8am to 6pm with no Sunday working. Environmental health confirms no objection, the use stays within E(g)(iii), and the letting completes without any application. The survey cost a fraction of the void period it avoided.

Where certainty is needed, a certificate of lawfulness of proposed use under section 192 of the 1990 Act is the only formal way to confirm that a use is lawful. An email from a planning officer confirming a view is not the same thing and will not satisfy a purchaser's solicitor.

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

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