Approved Document E: Resisting the Passage of Sound  

Learning Outcomes

By the end of this article, you should:

• Have a strong understanding of the purpose and requirements of Part E of the Building Regulations
• Be familiar with the critical guidance in Approved Document E and how it applies.
• Know the prescribed design standards, testing procedures, and compliance methods.
• Understand best practices for meeting airborne and impact sound insulation requirements.
• Recognize the importance of controlling reverberation through sound absorption.
• Be able to reference Approved Document E guidance during design and construction.

Introduction

Controlling the passage of airborne and impact sound between residences is a crucial consideration for health and quality of life. The Building Regulations of England and Wales recognise this through Part E – Resistance to the Passage of Sound. Compliance is mandated to ensure acceptable acoustic conditions.

This comprehensive guide covers the key guidance in Approved Document E, providing practical information on meeting the legal requirements for sound insulation and absorption. It aims to equip architects, builders, developers and homeowners to apply Part E properly. Topics covered include:

• How the requirements apply to different building types
• Design standards for construction to meet
• Testing evidence needed to demonstrate compliance
• Methods of compliance like Robust Details
• Standards for controlling reverberation in communal areas
• Consequences of failing to satisfy the regulations
• FAQs answering common questions

Understanding and adhering to the standards in Approved Document E through good acoustic design is vital for creating living spaces that are protected from unwanted noise.

Overview of Approved Document E

Approved Document E provides practical guidance on satisfying Part E of the Building Regulations for England and Wales. It lays out technical standards, testing procedures, and design methodologies that must be followed.

Part E recognises that noise can cause a disturbance, annoy neighbours, disrupt sleep and undermine the quality of life. Requirements aim to limit sound transmitted between spaces and control reverberation.

Specifically, Approved Document E specifies:

• Standards – Minimum performance standards for airborne and impact sound insulation and sound absorption
• Testing – Acoustic testing procedures are needed as evidence of compliance
• Design methods – Approaches such as using Robust Details to avoid testing
• Materials – Required acoustic ratings for absorptive materials   

By meeting the requirements and following the guidance, satisfactory resistance to the passage of sound will be achieved.

Scope and Exemptions

The requirements of Part E apply to walls, floors and stairs separating:

• Dwellings
• Rooms for residential purposes
• Dwellings and communal areas

Part E does not apply to detached or semi-detached houses. However, if these property types are converted into flats, the requirements do apply.

There are also exemptions for residential rooms where noise sensitivity is low, such as garages. Part E may be exempted where meeting the full standards is impracticable through intermediate floors.

Key Requirements of Part E

There are two main acoustic performance requirements specified in Part E:

1. Resistance to Airborne and Impact Sound

Constructions must provide adequate resistance to airborne sound transmission and impact noise between relevant spaces.

2. Control of Reverberation

Excessive reverberation in communal areas must be limited by absorbing sound. Adequate acoustic absorption must be provided in halls, corridors, stairwells and entrance halls.

By meeting these two requirements, Part E aims to ensure dwellings provide:

• Acceptable resistance to sound from other parts of the same building
• Protection against reverberation in common internal areas
• Reasonable resistance to sound from adjoining buildings

Design Standards for Sound Insulation

To satisfy Part E, walls, floors, stairs and other constructions must meet prescribed airborne and impact sound insulation design standards. These standards are specified in Section 1 of Approved Document E based on the type of adjacent space.

Some key minimum performance standards are:

• Dwelling-to-dwelling walls:  – Airborne sound insulation: DnT,w + Ctr ≥ 45 dB
• Dwelling-to-communal area walls: – Airborne sound insulation: DnT,w + Ctr ≥ 43 dB
• Stairwell walls/floors to dwelling:  – Airborne sound insulation: DnT,w + Ctr ≥ 43 dB
• Impact sound insulation: L’nT,w ≤ 58 dB  

There are also standards given for room-to-room walls, dwelling-to-stairwell floors, and several other constructions. Walls must meet requirements, whether solid or with apertures like windows or doors included.

Demonstrating Acoustic Performance

To demonstrate compliance with Part E, evidence of the acoustic performance of constructions must be provided through:

– Pre-completion testing

– A Robust Details approach

– Meeting design specifications

Testing is the default option to confirm the required standards have been met. But alternatives are permitted in certain cases.

Acoustic Testing  

Testing involves physical measurements of airborne and impact sound insulation once constructions are complete. It must be conducted according to the relevant BS EN ISO standards.

For newbuild flats, testing is required. Other situations where testing is mandatory include rooms for residential use and conversions where access to completed constructions is still available.

The person carrying out building work must arrange and pay for testing. Common tests include:

• Airborne sound insulation (DnT,w + Ctr )
• Impact sound transmission (L’nT,w)
• Reverberation time (Tmf,s)

Robust Details

Robust Details provides a way to avoid testing by using pre-approved high-performance constructions that comply with requirements. Constructions must be built precisely to the specifications given and certified by Robust Details Ltd.

Robust Details approved constructions include:

– E-WT-1 Timber Frame Separating Wall

– E-FC-1 Concrete Separating Floor

Using Robust Details can streamline compliance but care must be taken not to compromise performance through flanking sound paths.

Design Specifications

For some constructions, compliance can be demonstrated by meeting certain design specifications, such as minimum mass per unit area for floors. This avoids the need for testing.

Controlling Reverberation

In addition to insulation against direct airborne and impact sound, Part E also addresses reverberated sound within communal areas containing flats.

Excessive reverberation can cause acoustic discomfort. To control this, a proportion of surfaces must have sound absorptive finishes.

Section 2 of Approved Document E specifies the amount of absorption required based on the volume of the space. Materials must meet minimum class ratings for absorption.

For example, a stairwell measuring 200m3 would need a total absorption area of 22m2 at class C (absorption coefficient 0.60-0.75).

Methods of Providing Absorption

There are several ways to achieve the needed absorption:

• Selecting wall, floor, and ceiling finishes with the required class rating.
• Installing absorptive slabs or boards.
• Suspended absorptive ceilings.
• Calculations considering the combined absorption.  

Absorption can be distributed across different surfaces like walls and ceilings.

Health Impacts of Noise  

Understanding the health outcomes linked to noise is key to recognising the importance of Part E compliance. Studies have associated noise exposure with the following:

• Sleep disturbance and deprivation  
• Cardiovascular effects
• Cognitive impairment
• Mental health issues
• Reduced productivity
• Hearing impairment

By limiting the transmission of airborne and impact sound and controlling reverberation, Part E aims to avoid these adverse effects and support resident health and well-being.

Compliance and Enforcement

Responsibility for compliance lies with the person carrying out the building work. Sufficient evidence must be provided to building control inspectors to demonstrate Part E requirements have been satisfied.

If a failure to meet the standards is identified, inspectors can serve an enforcement notice requiring remedial action. Non-compliance can result in prosecution.

Fines and even imprisonment are possible for the most severe breaches. Developers, builders and architects should fully understand and adhere to Approved Document E.

Achieving Robust Acoustic Design

Careful design considering sound transmission paths, use of best practice construction techniques, testing, and appropriate material selection are key to successfully achieving the Part E performance standards.

Here are some recommendations for robust acoustic design:

• Detail junctions between constructions to limit flanking.
• Use full-fill insulating cavity masonry for separating walls.
• Opt for concrete over timber floors in apartments.
• Pay attention to penetrations, seals and weak spots.
• Follow Robust Details guidance precisely.
• Allow access for testing before completion.
• Seek specialist advice on remedial action if issues arise.

Following the comprehensive guidance in Approved Document E and employing good acoustic design principles allows the requirements for sound insulation and absorption to be satisfied reliably.

Conclusion

Preventing unwanted noise transfer between spaces is key for building functionality and occupant health. England and Wales recognise this need through Building Regulations Part E. Compliance should be integral to any residential project.

This guide has provided a detailed overview of Approved Document E and how to meet the legal requirements relating to sound insulation, acoustic testing and absorption of sound. Understanding and applying the standards and methodology is crucial for architects, developers, builders and property owners.

Please use this reference article to ensure Part E acoustic performance requirements are fulfilled successfully on your building projects. Contact an acoustic specialist for tailored advice.

Frequently Asked Questions