Public-Sector Security Fog Systems UK: A 2026 Buying Guide for Council Estates

Specify the system around the risk

For council estates, the first question is not which generator to buy. It is which assets, rooms and response-time gaps require active protection. Council depots, fleet compounds, civic buildings, plant rooms, records stores and unmanned service hubs each present different risks. A sound specification should begin with a site survey and a documented risk assessment covering access points, internal zones, valuable assets, alarm coverage, lighting, patrol arrangements, neighbouring premises and likely police response times.

The objective is to protect the volume of the secure area, measured in cubic metres (m³), rather than selecting equipment from a floor-area estimate alone. Ceiling height, partitioning, racking, doors and connected rooms all affect the protected volume. A council metals theft deterrent in a compact plant store may need a different arrangement from municipal depot break-in prevention across a large fleet compound. The same applies to government building security fog in a civic archive or equipment store.

Security fog is an active layer connected to the existing alarm infrastructure. Alarms detect. CCTV records. Density prevents. Passive security fails. When a confirmed alarm signal is received, security fog deploys in well under a single second to create zero visibility, denying an intruder the ability to locate, handle or remove assets. The fog is non-toxic, non-corrosive and leaves no residue, making it suitable for environments containing documents, medical equipment and public-sector stock when properly specified and installed.

97% of thefts avoided with security fog vs 17% with an alarm/CCTV alone.

Assess your estate with public-sector security fog systems UK

A site survey should record the volume of every proposed protection zone, the position of doors and access routes, the location of high-value assets and the relationship between the alarm panel and the fog system. It should also test whether a single zone or several linked zones provide the most appropriate control. The survey should identify any ventilation, fire-safety or building-management considerations and define the arrangements for safe isolation, testing and re-arming.

For procurement teams, the survey report becomes the basis of the Statement of Requirements. It should describe the security outcome required, the volume to be protected, the expected activation sequence, alarm integration, installer competence, handover information, user training and ongoing maintenance. The specification should refer to EN 50131-8 where applicable and require evidence that the proposed installation works with the organisation’s current alarm arrangements.

Density systems are approved for use with NSI and SSAIB security systems. This supports buyers seeking NSI compatible public-sector security and SSAIB approved fog systems without replacing an existing alarm or monitoring arrangement. Integration is normally achieved through alarm relay outputs and agreed activation logic. The installer should confirm compatibility with the relevant panel, signalling path and monitoring procedure before work begins.

Product selection should follow the protected volume and risk profile:

• Density Basic covers up to 390 m³ per shot and is suited to smaller stores, plant rooms and compact secure areas.
• Density UNIK covers up to 600 m³ and is a niche, battery-powered option for one high-value point only, such as a pharmacy cabinet, evidence room or isolated secure cabinet.
• Density 600C Line covers 600 m³ and can support chained arrangements where the design requires linked units.
• Density 900 covers 900 m³ for medium-sized rooms and secure areas.
• Density 2400 and Density 2400C Line cover 2,400 m³ per generator. The C Line option is intended for wider, multi-zone arrangements where linked coverage is required.
• Density HP6000 covers 6,000 m³ for larger depot, warehouse and plant environments.
• Density HP14000 covers up to 14,000 m³ per generator where a very large protected volume requires a high-output design.

The figures are starting points, not a substitute for a survey. A large council depot may require multiple protected zones rather than one oversized zone. A fleet compound may need security fog inside a building where keys, tools or control equipment are stored, while the external boundary is addressed through gates, lighting, detection and access control. Security fog is not a replacement for physical security, alarms, CCTV or operating procedures. It closes the gap between detection and response.

For NHS estates, NHS facility security systems should be assessed around pharmacy stores, medical-equipment rooms, controlled access areas and back-of-house stores. For schools and academies, the assessment should focus on safeguarding, duty of care, staff procedures and the protection of IT equipment and operational resources without creating unnecessary access risks. Police evidence store security requires careful coordination with local procedures, access controls and evidence-handling requirements. No public body should be presented as endorsing a supplier. The relevant estates, security and procurement teams must make their own assessment.

The same principle applies to civic site theft prevention. A civic building may contain IT equipment, keys, archives or operational materials, but may be largely unmanned overnight. A security fog system can be specified as the active deterrence layer that operates when an authorised alarm condition is met. What you can't see you can't steal.

For technical comparison, buyers can review the Density product range, the Density Basic system and Density UNIK. The Density case study archive can provide additional context, but each public-sector estate still requires a site-specific design.

Procurement should then consider route, standards, whole-life cost and assurance. Depending on the contracting authority and contract value, requirements may be advertised through Contracts Finder, a suitable framework or an approved e-tendering route such as ProContract. The Crown Commercial Service and current UK procurement guidance should be checked before a route is selected. The Procurement Policy Notes and guidance on technical specifications under the Procurement Act 2023 are useful starting points.

Scotland, Wales and Northern Ireland have different procurement frameworks and public-sector arrangements. Buyers should confirm the applicable rules in their jurisdiction rather than assuming that a route used by an English council applies across the UK.

A compliant evaluation should compare more than the initial equipment price. Consider the survey method, m³ coverage calculation, integration works, commissioning, training, fluid or consumable replacement, battery testing, fault reporting, annual maintenance and the availability of engineers. Ask suppliers to explain what happens after activation, how the alarm monitoring centre is notified, how the area is ventilated and how the system is returned to service.

Maintenance should be written into the contract from the outset. It should include scheduled inspection, functional testing, alarm-path testing, battery checks, consumable checks, fault diagnosis and records of service activity. Staff, contractors and attending responders should understand the system’s purpose and the local response procedure. Clear signage and documented isolation procedures are important, particularly where multiple departments share a building.

Insurance should also be discussed early. Active security systems such as Density security fog are increasingly mandated as a prerequisite of cover. This does not remove the need to follow the insurer’s specific requirements, and it does not mean that a fog system alone satisfies every policy condition. Procurement teams should request the relevant technical and installation documentation and share it with their broker, insurer or risk protection arrangement for review.

FAQ Box

How quickly does public-sector security fog deploy?
Security fog deploys in well under a single second after the appropriate trigger, creating zero visibility. The time required to fill the full protected volume depends on the selected generator, system design and room volume.

How is coverage calculated?
Coverage is specified in cubic metres (m³). A survey measures the protected volume and considers ceiling height, partitions, openings and connected areas. Density models range from Basic at 390 m³ to HP14000 at up to 14,000 m³ per generator.

Can a council retain its existing alarm and CCTV systems?
In most designs, yes. Density works with existing alarm infrastructure and is approved for use with NSI and SSAIB security systems. CCTV can continue to support investigation and verification, while security fog provides the active deterrence layer.

Which system is suitable for a council depot?
The correct model depends on the volume and layout. Basic may suit a small plant store, while 900, 2400, HP6000 or HP14000 may be considered for larger areas. A 600C Line or 2400C Line may be appropriate where linked zones are required.

Is Density UNIK suitable for an entire estate?
No. UNIK is a niche, battery-powered option for one high-value point only. It is not intended to be the flagship solution for large council buildings, depots or multi-room estates.

What should be included in a tender response?
Request the proposed m³ calculation, applicable EN 50131-8 documentation, NSI and SSAIB compatibility information, alarm integration method, installer details, commissioning plan, training, maintenance schedule, consumable costs, warranty and response arrangements.

Do public-sector organisations across the UK use the same procurement route?
No. Scotland, Wales and Northern Ireland have different procurement frameworks. Confirm the correct route and applicable guidance for the contracting authority before issuing a requirement.

Does security fog replace physical security or an alarm?
No. It should be assessed as part of a layered security design. Physical protection, detection, CCTV, access control, monitoring and response procedures remain important controls.

A well-written specification makes the buying decision more defensible. It links each proposed system to a recorded risk, a defined protected volume and an operational requirement. It also gives procurement teams a consistent basis for comparing proposals across council depots, fleet compounds, civic buildings and storage areas.

The central question is simple: can the site detect an intrusion, and can it do something meaningful before the response window closes? If an alarm only reports entry and CCTV only records the event, the organisation may still be exposed to loss. Density adds an immediate physical barrier while the incident is in progress. That is the practical meaning of active deterrence for public-sector estates.

For a site-specific recommendation, request guidance on public-sector security fog systems UK.