Fire Risk In Sustainable Timber Framed Construction And How To Manage It

Construction projects are under increasing pressure to use ‘sustainable materials’.

Timber or timber based products are frequently used as sustainable materials.

They can be traditional timber or Cross Laminated Timber type products (CLT).

After all, wood has embedded carbon right?

Just right for saving CO2!

Timber is becoming the ‘go to’ material to cut carbon emissions in construction and achieve a more sustainable outcome.

So far, so good.

But this creates a problem.

Most of us accept that more sustainable construction methods and materials are necessary.

However, Grenfell and the Hackitt Review have made us all understandably nervous of the fire risks in using timber based products for buildings particularly those over three storeys.

Who is affected?

Housing Associations, Local Authorities will need to manage fire risk in sustainable timber framed construction, along with their chosen contractors and developers.

The pressure for them to build social or affordable housing is considerable.

The pressure to build and develop them sustainably is huge.

This article will  dispel some of the fear and confusion of managing risks using timber based products in construction.

So what is the current position in the UK?

The Demand For Sustainable Construction

The UK construction industry is now under pressure to cut its carbon emissions.

“In 1990, emissions from this sector amounted to 9.3 million metric tons and in 2019 were approximately 13 million metric tons. This was roughly three percent of the total carbon dioxide emissions in the UK that year.” (Statista Article Ian Tiseo)

The pressure to reduce Carbon emissions will increase.

This pressure will come from the following:

  • UK Government.
  • Welsh Assembly Government ( declaring a’ climate emergency’ is one thing, what are you DOING about is another)
  • Financial Institutions (who increasingly seek ethical property developments).
  • Covid 19 has pushed ‘sustainability’ higher up the political & economic agenda.
  • Public pressure groups.

Therefore reliance on timber based products will increase.

 

The following quotation makes the case for timber in construction abundantly clear:

Andrew Carpenter, STA chief executive, said: “The shortage of housing in the UK is an issue that has been acknowledged by successive governments; we must ensure that all new build homes are delivered in a high-quality and sustainable manner.

“Furthermore, to deliver the volume demanded with the urgency suggested, then this is also achievable by using engineered timber solutions that are predominately manufactured offsite – this also alleviates the acknowledged skill-shortage faced by the construction industry.

 

Forward momentum on housing has been achieved and the STA is working actively with Welsh Government, supported by a number of Welsh unitary authorities to support the decision that all future affordable homes in Wales shall be timber frame.

Further STA support research and engagement with the insurance industry is also now well established.

The drive for sustainability in construction does not just apply to new developments though.

New commercial, flats, multi-occupancy, health and education buildings will all have to show momentum to zero carbon development.

Existing older buildings in need of renovation, refurbishment or re purposing can benefit from using timber products for sustainability.


Below is a link to a wonderful example from Ramboll of a 1960s building where the concrete frame was retained but the extension used timber saving 2200 tons of CO2.

Renovation and re purposing of existing buildings will become increasingly important.

https://ramboll.com/projects/ruk/the-green-house-cambridge-heath-road

 

So what’s The Problem?

So far, we know there is demand but we also know people are nervous about the fire safety aspect in delivering sustainable buildings using timber materials.

The inclination of the industry is to ‘push back’ against timber products due to legitimate concerns regarding fire safety post Grenfell post Hackitt review.

There are concerns on long-term insurance and retrospective works required should future legislation change.

There are also concerns about the skills of designers and installers to provide robust developments for use.

A lack of engagement at principal design stage with facilities and framework contractors on best sustainable maintenance regimes.

These concerns are entirely understandable but also misplaced.

A great deal of fear, confusion and trepidation to build using timber components comes from the following;

  • Seemingly complex and confusing regulations.
  • Scope for grossly misinterpreting these regulation.
  • Acknowledging and managing risk.
  • The reaction of the UK Insurance Industry (particularly RSLs).
    https://www.pbctoday.co.uk/news/mmc-news/timber-frame-fire-safety/80514/
  • Lack of early stage engagement with Fire Engineering Specialists.
  • Failing to ask the timber manufacturers for specific effects of fire on load bearing capability.
  • Understanding detail for firestopping and cavity barrier requirements.
  • Planning & communication with execution of proper installation from the design stage onwards (RIBA stages 4-5).
  • A suitable evidence based safety case for developments from concept design to full life cycle.
  • Suitable management and maintenance.

 

How To Embrace Sustainable Construction And Move Forward

Building with timber products does not have to be any different to building with traditional products.

Fire risks and safety at planning and design stage, during construction and post construction should be part of any construction plan.

To safely manage fire risks for building construction using timber products simply means you need early engagement with trusted advisors.

However, the FAILURE to engage early, results in the following issues we see on a regular basis:

  • Retrospective action is often needed on projects and results in costly remedial work.
    This includes everything from fire doors being unnecessarily specified to discovering down stream that sprinkler systems are required (Often due to the buildings operational use NOT its design Per Se).
  • Due to the above, profit margins become compromised. Someone has to pay?
  • Contractual wrangles – deciding who is right or wrong and who pays. Who to blame?
  • Project suffers delays and time money and resources are wasted.
  • The catastrophic trade off between profits and lives being put at risk?
  • Reputational risks to those parties to the development.
  • Passing the buck- no one wants to take responsibility. Sours business relationships.
  • Nasty surprises which could have been avoided by better upstream planning and engagement with the right people.

How can you avoid or mitigate the above and move forwards confidently? What is your strategy?

The key actions here are twofold:

1. Engage with Fire Risk Engineers as soon as possible.

This can even be before the design stage for timber based construction. For example, is the proposed building in close proximity to another building(s)? If so you need to know the Fire Risk implications of this BEFORE you go any further

2. Build the project plan with a fire strategy in mind.

Be mindful of the following:

  • Fire risk during construction will be required ( radiant heat assessment).
  • Fire treatment may be required for internal and external linings.
  • External wall systems may have to be non-combustible. This is dependent on function of the building, i.e. a block of flats or an office and its location.
  • Detail of systems, fire stopping and warranty specifications need review to make sure systems installed are safe.
  • Use of sprinklers within buildings would support timber frame and could be offset by reducing fire requirements in other areas.
  • Specification of timber that needs to be treated for fire resistance will require re evaluation as to its load bearing capability.

Summary

An initial check list might look something like this;

  • Know your battles upfront- find specialist help early.
  • Early engagement is vital – design stage – radiant heat assessments etc.
  • Collaboration- assemble the right team of specialists
  • Communication- avoid the silo effect – everyone is informed
  • Attention to detail-design changes – specification changes-QS involvement
  • Clear planning & consultation &documentation- a compliance audit trail.

 

If you have a project you wish to discuss please do not hesitate to call Dean Partridge by e mail Dean@greenhat-consulting.co.uk, and let him know your a member of WIC UK.