Data centres, storage and where new uses land in the order

Ask five planning officers what data centre use class applies and you will get at least three answers. The Town and Country Planning (Use Classes) Order 1987, as amended in 2020, does not name data centres, and a use that is not named falls to be classified on its actual character. In practice that means an argument between Class B8 storage or distribution and sui generis, and the answer turns on what happens inside the building rather than on what the industry calls it.

The classification decides more than it looks. It sets whether a future change of use is permitted, what the local plan policy tests are, and how a condition can control expansion.

How a use without a named class is treated

The Use Classes Order works by grouping uses. A use that falls within a class can change to another use in the same class without planning permission, because section 55(2)(f) of the Town and Country Planning Act 1990 takes it outside the definition of development. A use that falls outside every class is sui generis and any change to or from it requires permission.

Classification is a matter of fact and degree for the decision maker, informed by the primary purpose of the use, the character of the activity, and its planning effects such as traffic, hours, noise and employment. Industry labels carry no weight. A building described as a logistics hub may be B8, E(g)(iii) light industrial, or sui generis depending on what goes on in it.

Two consequences follow for anyone promoting a scheme. The description of development you apply for shapes the classification you end up with. And a permission granted for a described use is a permission for that use, so a later dispute about whether the use has changed is resolved against the description, not against the class.

Arguments for storage against sui generis

The case for Class B8 rests on the physical reality that a data centre stores things, in this case data, in racks, and that the building is essentially a secure warehouse with servicing.

The case against it is stronger, and it is the one most authorities now take. The Order's classes were written around activities with particular planning effects, and a data centre's effects do not match a warehouse's. Employment density is very low against a B8 benchmark. Vehicle movements are a fraction of a distribution unit's. Electrical load is orders of magnitude higher. Plant, cooling and standby generation dominate the building envelope and the external areas. Operating hours are continuous. None of that reads as storage in the sense the Order contemplates.

Treating the use as sui generis has a practical advantage for a local planning authority, because it means any material change away from the use needs permission and the authority keeps control of the site. Applicants sometimes resist that, and the resistance is usually misplaced: a sui generis permission with a clear description gives the operator certainty about what they may do, and the flexibility they lose is flexibility they would rarely use.

Say what you think the classification is in the planning statement, and give reasons. An application that leaves it to the officer will get the officer's answer.

Power, cooling and plant at planning stage

This is where the application succeeds or fails, and it is not really a use classes question at all.

The grid connection is the long pole. Capacity in many areas is constrained and connection dates are years out, which makes the connection offer a material piece of evidence about deliverability. Where the scheme depends on a new primary substation, the substation is development in its own right and may need its own permission or a separate consenting route.

Cooling drives the external design. Chillers, dry coolers and adiabatic systems occupy roof and yard space, they make noise, and where evaporative cooling is used, water demand becomes a live issue that the water undertaker will comment on.

Standby generation is the item objectors focus on. Diesel generators are typically sized to carry the full load, tested regularly, and held with bulk fuel storage that brings its own controls. The testing regime is what neighbours hear, and it is the thing to pin down in the application rather than leave to a condition.

Set all of this out with figures. An application that describes plant in general terms invites a condition requiring details to be approved later, which hands the authority a second bite at the design.

Noise from generators and chillers

Expect a full assessment against BS 4142:2014+A1:2019 for the continuous plant, with separate treatment of generator testing as a distinct, infrequent event.

The points that decide the outcome:

• The background sound level measured at the nearest residential receptors, including the quietest night-time period, because continuous plant is judged against the quiet hours
• Acoustic character corrections for tonality from fans and pumps, which are often the difference between an acceptable and an unacceptable rating level
• Cumulative assessment where other plant already exists on the site or nearby
• A separate scenario for generator testing, with the proposed hours, duration and frequency stated
• The residual position after mitigation, with the attenuation specified rather than assumed

A Noise Impact Assessment that deals with normal operation but leaves generator testing to a condition is the most common gap. Deal with it in the assessment, propose the testing regime yourself, and you keep control of it.

Employment land policy fit

Here the classification argument becomes a policy argument, and it is the one that most often causes trouble.

Most local plans protect allocated employment land and resist its loss to uses that deliver fewer jobs. A data centre on an employment allocation delivers a small number of high-value jobs on a large floorplate, so a policy written around jobs per hectare will not support it on a straight reading.

The counter-arguments are about economic function rather than headcount: the infrastructure role of the facility, the supply chain and construction employment, the business rates yield, and the fact that the site is retained in employment use rather than lost to housing. The December 2024 edition of the National Planning Policy Framework added data centres to the types of development identified as important to the national economy, which gives the argument a policy hook. Verify the position and the policy reference in the current edition published on 17 August 2026 before citing it, because that edition reorganised the Framework around policy codes.

An Employment Land Assessment that engages with the adopted policy on its own terms, rather than asserting national importance, is what moves an officer.

Security fencing and design

Operational security requirements conflict with design policy almost by definition, and the conflict has to be designed out rather than argued away.

Palisade fencing, rolling gates, wide sterile margins, high-mast lighting and blank elevations are what a security consultant asks for. What a design officer wants is active frontage, natural surveillance and materials that respond to context. The workable compromises are familiar: set the security line inside a landscaped margin, use mesh systems rather than palisade, break long elevations with material changes and recesses, and put the small amount of office accommodation on the street frontage.

Lighting needs its own attention, because a continuously lit compound in a dark area is a genuine amenity issue rather than a design preference.

Describing the use in the application

Write the description to match what you intend to do, in terms that would still make sense to an enforcement officer in fifteen years.

A workable description names the building type, the plant, the ancillary accommodation and the external works, and it avoids branding. Where the use is sui generis, say so in the planning statement and ask the authority to confirm it, because an unresolved classification is a defect that surfaces at the worst possible moment during a sale or a refinancing. The Planning Statement is where that case belongs.

Conditions likely to be imposed

Anticipate them and draft them yourself. The usual set covers plant noise limits at named positions with post-installation verification, generator testing hours and frequency, external lighting in accordance with an approved scheme, a restriction on additional plant without further permission, water use and cooling method, construction traffic management, and a landscape and boundary treatment scheme with a maintenance period.

A condition restricting changes of use within a class is only lawful where it is justified in the particular case, so if the use is classified within B8, expect the authority to seek exactly that restriction and expect to have to justify resisting it. The amenity test applied to light industrial use under Class E(g)(iii) shows the same tension in a different setting.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.