TEMPEST Shielding Requirements

Understanding TEMPEST Shielding: Protecting Sensitive Information from Electromagnetic Emanations

In an era where information security extends far beyond firewalls and encryption, defence and government facilities must contend with a lesser-known but critical vulnerability: compromising electromagnetic emanations. TEMPEST shielding represents one of the most sophisticated approaches to information security, designed to prevent the interception of classified data through unintentional electromagnetic signals. For facilities across Atlantic Canada, including military installations, government offices, and defence contractors in Nova Scotia, understanding and implementing TEMPEST requirements is essential for maintaining security clearances and protecting national interests.

TEMPEST—a code name that has become synonymous with the study and control of compromising emanations—encompasses a comprehensive set of standards, testing procedures, and countermeasures. These requirements affect everything from facility design and construction to the selection of electronic equipment and the implementation of operational security protocols. This guide provides an in-depth examination of TEMPEST shielding requirements relevant to Canadian defence engineering projects.

The Science Behind TEMPEST: How Electromagnetic Emanations Compromise Security

Every electronic device generates electromagnetic emanations as a natural byproduct of its operation. Computer monitors, keyboards, printers, and network equipment all produce signals that radiate through the air and can travel along power lines, network cables, and building infrastructure. These emanations, when intercepted and analysed by sophisticated equipment, can potentially reconstruct the original data being processed.

The physics underlying this vulnerability involves several mechanisms:

• Radiated Emissions: Electromagnetic fields propagate through free space from electronic components, cables, and circuit boards. These signals can be captured by antennas positioned outside secured areas, potentially at distances of hundreds of metres.

• Conducted Emissions: Signals travel along conductive paths such as power lines, telephone wires, and grounding systems. These can extend well beyond facility boundaries, providing collection opportunities at significant distances.

• Acoustic Emanations: Some equipment produces sounds that correlate with data processing activities. High-sensitivity microphones can capture these acoustic signatures for analysis.

• Optical Emanations: LED indicators and display screens can leak information through modulated light emissions that can be intercepted through windows or reflective surfaces.

The Canadian Centre for Cyber Security, working in conjunction with allied nations through established information-sharing agreements, maintains classified specifications detailing the precise vulnerability thresholds and required attenuation levels for different security classifications. Understanding these scientific principles is fundamental to designing effective countermeasures.

Canadian TEMPEST Standards and Regulatory Framework

Canada's TEMPEST requirements align closely with those of allied nations, particularly through the Five Eyes intelligence alliance. The Canadian government maintains several levels of TEMPEST protection, each corresponding to different threat environments and classification levels of information being processed.

TEMPEST Zones and Protection Levels

Facilities are categorised into protection zones based on their proximity to potential collection threats:

• Zone A: Applies to facilities where hostile intelligence services could potentially position collection equipment within 20 metres of the equipment being protected. This represents the highest level of protection requirement.

• Zone B: Covers facilities where the minimum distance to potential collection points is between 20 and 100 metres. Requirements are somewhat less stringent but still substantial.

• Zone C: Applies when controlled perimeters ensure a minimum 100-metre separation from potential collection positions. This allows for reduced shielding requirements in some applications.

For many facilities in Atlantic Canada, particularly those located in urban centres like Halifax or near international shipping lanes, Zone A or Zone B requirements typically apply due to the potential proximity of uncontrolled spaces.

Equipment Standards

Electronic equipment used in TEMPEST-controlled environments must meet specific standards:

• NATO SDIP-27 Level A (formerly AMSG 720B): Equipment meeting this standard is approved for use in Zone A environments and provides the highest level of emanations security.

• NATO SDIP-27 Level B (formerly AMSG 788A): Suitable for Zone B environments with moderate protection requirements.

• NATO SDIP-27 Level C (formerly AMSG 784): Provides tactical protection suitable for Zone C environments.

Canadian defence contractors and government agencies must source equipment from approved suppliers listed in the Canadian Industrial TEMPEST Programme (CITP) or equivalent allied nation programmes.

Architectural and Construction Requirements for Shielded Facilities

Constructing a TEMPEST-compliant facility requires careful integration of shielding elements into the building architecture from the earliest design phases. Retrofitting existing structures, while possible, typically proves significantly more expensive and may not achieve the same performance levels as purpose-built facilities.

Shielded Enclosure Construction

The fundamental approach to TEMPEST shielding involves creating a continuous conductive barrier around the protected space. Several construction methods are commonly employed:

• Welded Steel Enclosures: Panels of steel plate, typically 3mm to 6mm thickness, are continuously welded to create a sealed electromagnetic barrier. This method provides excellent shielding effectiveness, often exceeding 100 dB attenuation across the frequency spectrum of concern.

• Modular Panel Systems: Pre-fabricated shielded panels featuring steel or copper mesh bonded to substrate materials offer faster installation and easier modification. High-performance systems can achieve 80-100 dB attenuation when properly installed.

• Architectural Shielding: Copper or steel foil applied to walls, floors, and ceilings, with careful attention to seam bonding, provides a cost-effective solution for lower-classification requirements. Attenuation levels of 40-60 dB are typical.

Critical Penetration Points

Every penetration through the shielded envelope represents a potential vulnerability requiring specific engineering solutions:

• Doors: Shielded doors must incorporate continuous knife-edge or fingerstock contacts around the entire perimeter. Door frames require precise installation to maintain contact pressure and prevent gaps. Automatic door closers and position sensors ensure doors remain sealed during operations.

• Windows: When operational requirements necessitate windows, they must incorporate conductive mesh or transparent conductive coatings. Wire mesh embedded in glass can provide 40-60 dB attenuation, while specialised coatings may achieve 30-40 dB.

• Power Entry: All electrical power entering the shielded space requires filtering through TEMPEST-rated power line filters. These devices must provide adequate attenuation across the protected frequency range while handling the required current loads.

• Signal Lines: Data and communication cables penetrating the shield require either fibre optic conversion or filtered connectors. Waveguide-below-cutoff entries provide excellent performance for ventilation and other non-electrical penetrations.

• HVAC Systems: Air handling requires waveguide ventilation panels designed to attenuate electromagnetic signals while permitting adequate airflow. Honeycomb waveguide structures with cell dimensions calculated for the frequencies of concern are standard solutions.

Grounding and Bonding Requirements

Proper grounding is essential to shielding effectiveness. All metallic elements of the shield must be electrically bonded to create a continuous conductive envelope. The facility ground system must be designed to prevent ground loops while providing low-impedance paths for any intercepted energy. In Nova Scotia's coastal environment, particular attention must be paid to corrosion protection of grounding systems due to salt air exposure.

Testing and Certification Procedures

Completed TEMPEST installations require rigorous testing to verify compliance with applicable standards. The certification process involves multiple phases and specialised measurement equipment.

Shielding Effectiveness Testing

Before installing sensitive equipment, the shielded enclosure itself must be tested to verify its attenuation performance. Testing typically involves:

• Radiated Emissions: A calibrated signal source is placed inside the enclosure while sensitive receivers measure signal levels outside. Measurements are taken across the protected frequency range, typically 10 kHz to 10 GHz or higher.

• Conducted Emissions: Power line filters and signal line penetrations are tested to verify adequate attenuation of signals that might conduct along these paths.

• Penetration Analysis: Each door, window, ventilation panel, and other penetration is individually tested to identify potential weak points.

System-Level TEMPEST Testing

Once equipment is installed, the complete system undergoes TEMPEST testing to verify that emanations are below acceptable thresholds. This testing is conducted by accredited laboratories and must be repeated whenever significant changes are made to equipment or facility configurations.

In Atlantic Canada, facilities requiring TEMPEST certification must work with approved testing organisations recognised by the Canadian Centre for Cyber Security. The nearest major testing facilities are located in the Halifax region, serving the defence and government sectors throughout the Maritime provinces.

Practical Implementation Considerations for Atlantic Canadian Projects

Implementing TEMPEST requirements in Nova Scotia and the broader Atlantic Canadian context presents unique considerations that project managers and engineers must address.

Climate and Environmental Factors

The Maritime climate poses specific challenges for TEMPEST installations:

• Humidity Control: High humidity levels can affect shielding material integrity and promote corrosion at bonding points. Proper environmental controls within shielded spaces are essential.

• Temperature Cycling: Significant temperature variations between seasons can cause expansion and contraction of shielding materials, potentially opening gaps at seams and penetrations. Flexible bonding solutions and regular inspection protocols help mitigate this risk.

• Salt Air Exposure: Coastal facilities must employ enhanced corrosion protection for all grounding systems and external shielding components.

Supply Chain Considerations

TEMPEST-rated materials and equipment often have extended lead times and limited supplier availability. Projects in Atlantic Canada should account for:

• Shipping times from manufacturers, many located in central Canada or internationally

• Requirements for secure handling of classified specifications and materials

• Limited local availability of specialised installation contractors with appropriate security clearances

• Coordination with federal agencies for equipment approvals and certifications

Integration with Other Security Requirements

TEMPEST shielding rarely exists in isolation. Facilities typically must also meet requirements for physical security, cybersecurity, and personnel security. Effective project planning integrates these requirements to avoid conflicts and optimise costs. For example, access control systems must be compatible with shielded enclosures, and network architecture must accommodate the air-gapped configurations often required in TEMPEST environments.

Cost Factors and Project Planning

TEMPEST shielding represents a significant investment, and understanding cost drivers helps organisations plan effectively and make informed decisions about protection strategies.

Typical cost factors include:

• Enclosure Construction: Welded steel enclosures typically cost between $500 and $1,500 per square metre of protected floor space, depending on size, configuration, and required performance level.

• Penetration Hardware: Shielded doors range from $15,000 to $75,000 each depending on size and performance requirements. Power line filters, depending on current capacity and attenuation requirements, cost from $2,000 to $20,000 per unit.

• Testing and Certification: Initial certification testing typically costs $25,000 to $100,000 depending on facility size and complexity.

• Ongoing Maintenance: Annual inspection and recertification costs should be budgeted at approximately 5-10% of initial installation costs.

Early engagement with experienced engineering firms can help identify cost-effective approaches while ensuring compliance with applicable requirements.

Partner with Experienced Defence Engineering Professionals

TEMPEST shielding requirements demand specialised expertise spanning electromagnetic theory, construction practices, and regulatory compliance. Successfully implementing these requirements requires careful planning, precise execution, and thorough testing at every phase.

Sangster Engineering Ltd., based in Amherst, Nova Scotia, brings extensive experience in defence engineering projects throughout Atlantic Canada. Our team understands the unique challenges of implementing sophisticated security requirements in the Maritime context, from managing supply chain logistics to addressing climate-specific concerns. We work closely with clients from initial concept development through construction oversight and final certification, ensuring projects meet all applicable TEMPEST requirements while optimising costs and schedules.

Whether you are planning a new secure facility, upgrading an existing installation, or require technical consultation on TEMPEST compliance, contact Sangster Engineering Ltd. to discuss how our defence engineering expertise can support your project's success.

Partner with Sangster Engineering

At Sangster Engineering Ltd. in Amherst, Nova Scotia, we bring decades of engineering experience to every project. Serving clients across Atlantic Canada and beyond.

Contact us today to discuss your engineering needs.