How LABC Warranty assesses MMC and OSM products for acceptance

With construction costs, efficiency, and sustainability increasingly a part of the conversation around expanding the UK’s housing stock, demand and interest in off-site manufactured systems has only increased.

Off-site manufacturing (OSM) and modern methods of construction (MMC) are often used interchangeably and describe construction methods that rely on components being manufactured in a factory, transported to a site, and then assembled on location.

While MMC is in-demand, and the market expands with more products to solve the issues found on site, no product or system is a solve-all panacea.

Every OSM or MMC product has conditions and limitations that will dictate the boundaries of its use on certain projects, with those limits determined by the properties of the system itself and local conditions.

LABC Warranty undertakes a rigorous review of any innovative system before it’s accepted for use on a site covered by our warranty, with a list of acceptance conditions, an individual system’s scope, and that’s systems limitations clearly defined in the System Acceptance Document.

Please refer to our system acceptance register where you find current list of accepted systems.

This article explores what that process entails and how you might prepare to submit a system for review by the LABC Warranty Innovations Team.

The LABC Warranty MMC and OSM acceptance process

What LABC Warranty looks for, and how you might prepare

The process for MMC and OMS systems to gain formal acceptance from LABC Warranty is thorough. Systems must satisfy the safety and acceptability requirements we demand, and also complement the requirements laid out in the LABC Warranty Technical Manual and dedicated Innovative System Review Technical Guide Document.

The review process focuses on the system design, manufacturing, and installation philosophies. This process runs from system inception to its delivery and erection on site, along with long-term reparability and maintenance considerations.

All proposed systems must be designed and manufactured using certified components, have quality management systems in place, and must be accepted by our Innovation Team.

Details and limitations of LABC Warranty acceptance

Just as no MMC system is applicable to every situation, acceptance from LABC Warranty to use MMC or OMS is no assurance that the product can be used anywhere, on any site. There are strict limitations to any acceptance.

All buildings and projects are different. Where a building is constructed using an innovative building system, the building will also require a project-specific review and approval that accounts for the site-based variations such as loadings, choice of cladding, exposure, and more.

LABC Warranty’s acceptance is not a Third Party Product Approval from a UKAS-accredited testing body nor any form of Building Regulation approval. It is purely to recognise that this system/product can meet our warranty requirements and must not be considered to be anything else. The acceptance only recognises that the system meets LABC Warranty’s technical requirements under prescribed conditions of use.

As part of our warranty application process, property developers must ensure that any deviations proposed on-site from the originally reviewed innovative system are pre-accepted by the Innovations Team in line with the requirements of our Technical Manual.

The system’s provider will also need to meet Building Regulation requirements and secure approval from a Building Control body for any proposed project.

The System Acceptance process

The internal process for system acceptance can be broken down into four key areas:

  1. An initial free assessment of the system to determine whether the proposed product broadly satisfies our performance standards. If the product doesn’t meet those standards, we’ll contact the manufacturer and provide feedback.
  2. Following the initial assessment, a detailed review can take place, subject to an assessment fee being paid. A Design Review Report [DRR] document will be issued, along with a system-specific ShareFile link to upload documentation. Following this, there will be a full desktop study of the manufacturer’s system.
  3. If the second stage is successful, a factory inspection will be conducted. If LABC Warranty is satisfied with the system design, fabrication, and the quality management, the system will be issued with a provisional acceptance for a trial site.
  4. The system will be deployed on an initial trial site, which will be registered to LABC Warranty for warranty purposes. The system manufacturer and developer will need to demonstrate the products meets the requirements of the LABC Warranty Technical Manual, and is in line with recommendations produced by the initial three stages of review. Once the trial site has shown that the system can achieve its aims, both in line with the manual’s guidance and according to the guidance requested by LABC Warranty, the system can pass into full acceptance. Acceptance is limited to one year, and requires renewal on an annual basis.

What kind of documents to prepare for an assessment

In addition to the practical assessment, LABC Warranty will need to see a variety of documentation relating to the system in review.

The system owner, usually the manufacturer, must provide the system manual that characterises the system, outlining its build-up, material specification, relevant performance and the systems limitations of use.

The system manual should cover all possible variants of the proposed system, explain which elements are classified as standard system components and which may vary on a project-by-project basis. Please refer to detailed list of required information in the ‘Innovative System Review Technical Guide Document.’

This is likely to include:

  • Design philosophy – A description of your system and the relevant standards to which the system has been designed to satisfy.
  • Durability assessment – An assessment of the likely whole-life performance of your system.
  • Transport, storage, and installation – Details of how the system will be protected from weather and other damage during the process of moving the system to site until installation.
  • System limitations – The manufacturer will be asked to define the limitations of the system, including which other building materials and components it should not interact with, maximum height, exposure etc.
  • Identification and traceability – All components of your system must be identifiable, including dimensions, properties, tolerances, and the standard against which these components have been assessed. Every manufactured element should be able to be traced, and hits history determined, with every element having its own individual and unique identification number assigned, from assembly to installation.
  • Demonstration of performance – All relevant system information for all proposed system variants.
  • Behaviour in relation to fire – Demonstration that the system meets the fire performance requirements in Building Regulations, and assessment of the anticipated fire performance in relationship to life safety, property protection, and environmental impact.
  • Resistance to moisture – Evidence that the system will adequately protect its residents from the harmful effects of excess moisture, and address the health and safety of the occupants.
  • Resistance to the passage of sound – Evidence that the walls and floors provide necessary airborne and impact sound insulation for the intended use of the building.
  • Energy efficiency and ventilation – Demonstration that the system will comply with building regulations and other and other requirements in regards to the energy and efficiency and ventilation.

Please note that this is not intended to be an exhaustive list of documentation or evidence requested when assessing a new OSM/MMC product for use on sites covered by LABC Warranty.

The outcome of the process

Once accepted, a System Acceptance Document will be supplied to the system manufacturers outlining scope of acceptance, limitations and conditions of acceptance, with the LABC Warranty logo.

Validity of the acceptance document is visible in the document itself, but in addition eventual changes in acceptability are updated on our website.

This system can then be used on sites covered by LABC Warranty’s latent defects insurance, in accordance with the specific conditions laid out in the acceptance document.

Are you seeking system acceptance?

This advice here is not comprehensive, our intention is to offer you an overview of the acceptance process, and an impression of what to expect LABC Warranty to ask of you during the application process.

If you are an MMC manufacturer seeking LABC Warranty’s System Acceptance to use your systems on sites covered by LABC Warranty, get in touch.

The first port of call for any manufacturer seeking to have their OSM or MMC systems accepted for use on an LABC Warranty site is to get in touch. Email us on

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Please Note: Every care was taken to ensure the information in this article was correct at the time of publication. Any written guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant Building Regulations or applicable technical standards. However, for the most up to date LABC Warranty technical guidance please refer to your Risk Management Surveyor and the latest version of the LABC Warranty Technical Manual.

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