No one could easily forget about the deadliest fire tragedy that occurred at Grenfell Tower in London recently, on June 14. The fire claimed more than 80 casualties and the loss of homes for the residents.

It has been widely reported that the investigation blames the cause of this tragedy on flammable materials used in the façade and that it contributed to the spread of the blaze.

Now we come to look at how and why the fire spread and should there be ways that engineering design could be a crucial part in stopping or slowing the fire and minimize the possibility that the fire engulfed the whole tower.

Meinhardt, as an Engineering Consultant company with a well-established Meinhardt Façade Technology department, discusses why the blaze at Grenfell Tower was a catastrophe. What could have been done to avoid and minimize the fire in terms of the building’s Façade and further, how Meinhardt’s standards and design approach in Façade Engineering mitigate the risks.

Grenfell Tower

Aluminium Composite Panel (ACP) and insulation were used in Grenfell Tower, according to the reports resulting from different investigations. These showed that the ACP used was “Reynobond” with Polyethylene (PE) core, and Celotex RS5000 insulation. The PE core together with insulation and the air gap contributed to the spread of fire, as standard PE grades, although low in thermal conductivity are combustible if it comes in direct contact with a high intensity heat source, such as an open blaze.

Meinhardt’s Standard Approach

Aluminium Composite Panel (ACP) is one of the most common materials used in façade cladding. However, selection of proper ACP needs to be considered seriously. At Meinhardt, we only specify ACP products that compiles with all the relevant international codes. We also have further technical requirements stipulated in our specifications in our projects. Some of our main specifications are as below:

• The core material shall be non-combustible mineral filled core and shall be free  of voids and/or airspaces and not contain foamed insulation. Products laminated sheet by sheet in a batch process using glues or adhesives between materials are not acceptable.
• All composite panels shall not consist of toxic material.
• All composite panels shall be of consistent high quality, regardless of sources.
• Fire resistance of aluminium composite shall comply with BS 476 Part 6 Class 0 & BS 476 Part 7 Class 1, UBC standard 26-1 / NFPA 259, UBC standard 26-9 / NFPA 285, and EN 13501-1.
• Composite panel manufacturer shall have a minimum of 15 years’ experience in the manufacture.

To clarify, Meinhardt does not approve the use of ACP with PE core similar to the one used in Grenfell Tower in any of our projects.

One of the main materials used in fire a stopping system is an internationally compliant, high density fire stop insulation material known as “Rockwool”. Rockwool fire stop insulation is one of the approved products specified for all Meinhardt’s Façade projects. By installing Rockwool between the building structure and its façade at every floor, the blaze cannot shoot up through the gap and would at least slow the spread of the fire.

An air gap between ACP cladding and the structure in a rain screen cladding is inevitable, as it is required for installation tolerance and keeping the cladding plumb. But the standard is that all continuous wall cladding must have a proper fire stopping system or material. These materials are used to seal openings and joints of fire-resistance rated walls or floor assemblies.

With Meinhardt’s standard, we always ensure that right materials are carefully selected and a proper firestop system is put in place. These safety elements are always treated with the highest importance, properly considered and never neglected.

Roger Cua
Executive Façade Manager