Security Fog Devices
PURPOSE AND ROLE IN SECURITY SCHEMES
Security fog devices—also known as smoke security devices—are increasingly used as part of integrated security strategies to deter intruders and reduce theft opportunities. These systems are not intended to replace conventional physical protections or intruder alarms but should be considered as complementary technologies within a layered security approach.
CORE OBJECTIVE
To rapidly impair an intruder’s ability to steal by deploying a dense, non-toxic fog that obscures visibility and frustrates criminal activity, particularly during the critical moments of unauthorised entry.
APPROPRIATE APPLICATIONS
Security fog devices are particularly suitable for premises where conventional security controls are insufficient or impractical. Examples include:
Repeat-targeted premises where existing physical and electronic security measures have failed to prevent losses.
Physically vulnerable structures such as Portakabins, temporary buildings, or lightweight outbuildings (e.g., golf pro shops).
Listed buildings or conservation areas where security upgrades are restricted by planning constraints.
Targeted risk premises with known police response delays or increased risk of ‘out-of-hours’ attacks.
High-value retail environments prone to smash-and-grab thefts (e.g., jewellers, technology outlets).
Warehousing/storage of high-theft-attractiveness materials such as non-ferrous metals, high-end electronics, or tobacco products.
Note: Security fogging should be positioned as an intervention mechanism to delay or frustrate offenders until police or response personnel arrive, not as a primary deterrent or detection method.
INSTALLATION AND OPERATIONAL CONSIDERATIONS
Security fog devices must be installed strictly in accordance with manufacturer guidance, with careful consideration of layout, activation protocols, and room size. The following standards and requirements apply:
Compliance Requirements:
Systems must be manufactured, installed, and maintained in accordance with BS 7939: Code of Practice for the Manufacture, Installation and Maintenance of Smoke Security Devices.
Devices should be linked to the intruder alarm system, with defined triggering protocols.
The system must be serviced and tested periodically as per manufacturer recommendations.
Coordination with Authorities:
Prior to installation:
Written notification must be provided to the local police and fire authority.
This ensures responders are informed and can distinguish security fog from actual fire-related smoke when responding to an alarm activation.
Unsuitable Environments:
Fog systems may not be appropriate in certain high-sensitivity settings due to the potential for residue or airborne contamination, such as:
Food production and storage areas
Pharmaceutical or medical-grade environments
Precision manufacturing facilities
A thorough risk-benefit analysis should be completed before installation in such environments, considering regulatory compliance (e.g., HACCP) and hygiene standards.
RISK ENGINEERING GUIDANCE
When evaluating the suitability or effectiveness of a fogging system during surveys or proposals, consider the following:
Vulnerability of access points (e.g., glazing, lightweight doors).
Visibility obfuscation—is the fog volume and deployment speed appropriate for the protected space?
Ceiling heights and room volumes—impact on fog dispersion time and effectiveness.
Integration with intruder alarm and CCTV—ensures timely deployment and event verification.
Post-incident clean-up implications and protocols.
Maintenance schedule—documented and up to date.
Risk Improvement Wording: Refer to RiskSTOP’s standard risk improvement templates for fogging systems where a formal recommendation is justified.
COST AND JUSTIFICATION
Security fogging systems vary in cost depending on:
Number of devices required,
Integration with alarm systems,
Spatial coverage needs,
Installation complexity.
Given the relatively modest capital outlay compared to high-value stock losses, such systems are generally considered cost-effective in high-risk applications, particularly where physical upgrades are restricted or ineffective.
REFERENCE GUIDANCE
Risk Engineers are advised to consult the following documents for further detailed information:
RISCAuthority S7 – Security Fog Devices: Guidance on system function, selection criteria, and operational best practice.
Association of Insurance Surveyors (AiS) Security Fogging Code of Practice: AIS-Guidelines-Security-Fogging.pdf
SUMMARY
Security fog devices serve as a valuable secondary line of defence in a comprehensive security strategy. While not suitable for every environment, they are particularly effective in high-risk, high-value, and physically constrained premises. Proper installation, integration with existing systems, and coordination with emergency services are critical to ensure effectiveness and avoid unintended consequences.