Fire Safety and Sound Insulation—What Are the Requirements for Sound-Insulating Materials?

Fire safety and sound insulation must be designed together. A material may be effective against airborne sound, vibrations, or echoes without necessarily meeting the fire safety requirements applicable to the location where it is to be installed. Therefore, it is not possible to select a product based on terms such as “sound-insulating,” “sound-absorbing,” “non-combustible,” or “heat-resistant” and then assume that the entire structure is approved.

For new projects, the Swedish National Board of Housing, Building and Planning’s new building regulations will apply in full as of July 1, 2026. The basic principle is that building products and materials must have known and documented properties when these are relevant to the building’s fire protection. The required performance is determined by the context: the conditions of the building and its use, the material’s location, the structure’s function, and the designed solution.

It is important to distinguish between two types of properties. Reaction to fire describes how a material contributes to the development of a fire and may also include fire gases and burning droplets. Fire resistance refers to a building component’s ability, for example, to maintain load-bearing capacity, prevent the penetration of fire and fire gases, or limit temperature rise for a specified period of time.

A sound-insulating wall must therefore be evaluated as a system. Cladding, sound-insulating layers, insulation, studs, fasteners, joints, and penetrations all affect the result. The same applies to sound absorbers in ceilings or on walls: the product’s documentation must cover the specific variant and the intended installation.

Pay special attention when the work involves a fire compartment boundary. According to the Swedish National Board of Housing, Building and Planning’s definition, penetrations and connections are also included in the boundary. If a cable, duct, screw, joint, or other detail compromises the verified solution, both the fire and sound performance may be affected. Therefore, review existing fire protection documentation and consult a fire safety expert when the measure involves structural changes, deviates from documented installation procedures, or affects a critical building component.

SilentDirect’s product documentation can be used to select products based on acoustic issues, but it does not, on its own, provide sufficient support for determining a product’s fire rating or the fire resistance of the entire structure. Always request up-to-date documentation before specifying a SilentDirect material for a fire-code-regulated application.

Fire Safety Terms

Reaction to Fire

This property describes how a product or material behaves during the initial stage of a fire. For surface finishes on walls and ceilings, the main classes A1–F are used along with relevant supplementary classes.

Fire gases

The supplementary designation “s” is used to classify the amount of fire gases emitted by certain materials and surface finishes. It is not sufficient to compare only the main class if the requirement also includes an “s” class.

Burning droplets

The supplementary designation “d” is used for burning droplets or particles. This aspect must also meet the requirement for a specified material class to be considered satisfied.

Fire resistance

Fire resistance refers to the performance of a building component over a specified period of time. “R” stands for load-bearing capacity, “E” for integrity against fire and fire gases, and “I” for limiting the temperature on the side not exposed to fire.

Fire compartment and fire compartment boundary

A fire compartment is separated to limit the spread of fire to the rest of the building. The fire compartment boundary includes the structure as well as relevant penetrations and connections to other building components.

Declaration of Performance

For construction products covered by a harmonized standard, the Declaration of Performance specifies the product’s declared characteristics. This information must be compared with the project’s requirements and the intended use.

CE Marking

CE marking does not automatically mean that the product is suitable for all applications. The Swedish National Board of Housing, Building, and Planning states that the marking itself is not an approval or proof of suitability for a specific application.

Verified Design

A wall, floor structure, or suspended ceiling does not automatically achieve a specific fire rating simply by choosing a single material. The entire construction and installation must correspond to the solution whose performance has been verified.

Loose furnishings

Movable furnishings, such as furniture, tables, chairs, freestanding storage units, and similar equipment, are not part of the building’s permanent structural elements and are therefore not normally subject to the fire-resistance classification requirements that apply to, for example, walls, doors, and surface finishes.

Loose furnishings therefore do not need to meet a specific fire resistance class, provided that no special requirements apply to the specific activity or location in question. However, the furnishings must be placed and used in such a way that they do not obstruct escape routes, impair accessibility, or otherwise negatively affect the building’s fire protection.

Special consideration should be given to the amount of combustible material and its placement in or immediately adjacent to escape routes.

A Step-by-Step Guide to Ensuring Fire Safety

The right approach starts with the building and the finished structure, not with a standalone product. The following checklist will help you distinguish between acoustic preferences, mandatory requirements, and documented performance. For fire compartment boundaries, escape routes, or other critical areas, we always recommend consulting a fire safety expert.

1. Define the acoustic problem

First, determine whether the goal is to reduce sound between rooms, dampen vibrations, or reduce echoes within the same room. Sound insulation is often based on mass, density, and decoupling. Sound absorption, on the other hand, addresses sound reflections and reverberation. This distinction determines which products are acoustically relevant, but not which fire safety requirements apply.

2. Determine which part of the building is affected

Note whether the material will be installed exposed on a wall, in a ceiling, behind cladding, in a utility space, or inside a partition. Also verify whether the wall, door, floor joists, or connection forms part of a fire compartment boundary. The same material may need to be evaluated differently depending on its location and installation method.

3. Check which regulations the project follows

The Swedish National Board of Housing, Building and Planning’s new building codes apply in full to new projects as of July 1, 2026. For older, ongoing projects, transitional provisions and previous decisions may be relevant. Base your approach on the building permit, notice of commencement, fire protection description, and the project’s other documents rather than mixing solutions from different regulatory systems. Read more in the Swedish National Board of Housing, Building and Planning’s guidance on fire safety.

4. Identify the required fire performance

Check whether the requirement applies to the material’s reaction to fire, the properties of the surface layer, a building component’s fire resistance, or multiple properties simultaneously. For wall and ceiling materials, a class may consist of a main class and supplements for fire gases and burning droplets. For a fire-separating building component, requirements may instead be expressed through, for example, E and I together with a time value.

5. Request documentation for the exact product variant

Check the Declaration of Performance, CE information (where applicable), classification report, technical data sheet, and installation instructions. The product name alone is not sufficient. The documentation must correspond to the correct thickness, surface finish, color or fabric variant, substrate, adhesive, fastening method, and installation method. Also verify the validity, scope, and any limitations.

SilentDirect’s product matrix specifies acoustic applications but does not provide sufficient fire data for this article to specify the fire rating of an individual SilentDirect product. Therefore, request current documentation before specifying or purchasing if fire performance is critical.

6. Evaluate the Entire Structure

If a wall is to be soundproofed, all layers must be assessed together. An acoustically effective solution may, for example, include a heavy layer that SilentDirect MLV, porous absorption, studs, and new panel layers. This does not mean that the structure automatically achieves a certain level of fire resistance. The construction must correspond to a verified solution or be dimensioned and verified for the specific project.

Decoupling is important for sound insulation and vibration damping. Material contact between studs and surrounding surfaces can transmit vibrations. SilentDirect Seal may be acoustically relevant between contact surfaces to reduce vibrations and sound leakage, but its use must also be compatible with the fire-rated design documented in the technical specifications.

7. Preserve the penetrations and joints of the fire compartment boundary

The Swedish National Board of Housing, Building and Planning (Boverket) states that a fire compartment boundary also includes penetrations, installations, joints, and connections that affect its separating capacity. A standard acoustic joint compound, tape, or sealing strip must therefore not be treated as a fire seal without documented support. Use the prescribed and verified fire sealing solution where required. Read more at Boverket about fire compartment boundaries.

8. Check Fastening and Installation

A classification may depend on how the product is installed. A different type of screw, denser or sparser fastening, a different adhesive, a new substrate, or an air gap can alter the conditions. Follow the installation instructions and document any deviations before the product is installed. Do not install sound absorbers over detectors, sprinklers, smoke exhaust systems, signage, or other safety features.

9. Coordinate Acoustics, Fire Safety, and Building Services

Sound insulation must not block ventilation or impede the function of building services. Additionally, check for evacuation routes, accessibility, load-bearing capacity, moisture, and maintenance. A fire safety consultant, acoustician, and structural engineer may need to coordinate their requirements when the solution involves multiple building components.

10. Document the Final Solution

Save product documentation, drawings, photographs, installation instructions, and records of inspections performed. For measures requiring a building permit or notification, fire protection must be documented as required. The Swedish National Board of Housing, Building, and Planning (Boverket) describes fire protection documentation as an important basis both for the finished building and for future modifications. Review the requirements on the page regarding fire protection documentation.

In short, sound performance, fire performance, and proper installation must be verified individually and then function together. Do not make any fire safety assumptions based on a product’s appearance, material name, or marketing.

Sound-insulating materials that require proper fire safety assessment

The products listed below have various acoustic properties, ranging from mass and sealing to echo absorption. This presentation does not constitute a statement regarding fire rating or approved use. Always check the current product documentation, specified design, and the project’s fire requirements before the material is installed or applied as a surface layer.

SilentDirect MLV is a heavy-duty MLV barrier for structures where mass is needed to dampen airborne sound. The product can be mechanically fastened or clamped between layers of panels, depending on the substrate.

SilentDirect Polaric is used on sheet metal, metal, and other hard surfaces where mass, sealing, and vibration damping are required in a single layer. The installation and surrounding structure must be evaluated for the specific application.

SilentDirect Seal is a self-adhesive sealing strip for gaps, joints, and contact surfaces. The product must not be equated with a fire-sealing product without documented support for that use.

SilentDirect Aluminum Sealing Tape is intended for sealing joints, seams, and aluminum-clad transitions. A tight acoustic joint is not automatically a verified fire seal.

PES ceiling is a ceiling absorber designed to reduce echo and reverberation. Check the documentation for the correct variant, surface, mounting method, and placement before installation in a space subject to fire safety regulations.

PES wall is a wall absorber designed to reduce speech noise and harsh reflections. The product’s acoustic performance alone does not determine whether it meets the requirements for the specific wall or surface layer.

PES for structural ceilings is installed in existing structural frameworks to improve room acoustics. The entire suspended ceiling system, installations above it, and the material’s documented properties must be included in the assessment.

Acoustic wall textile is a thin acoustic textile designed for supplemental wall sound absorption. Since it is installed on a visible wall surface, it is particularly important to verify which surface layer requirements apply in the space.