The use of flammable cladding in China: A site study 2020

Notwithstanding subsequent tragedies across the world, some countries, even in 2020, continue to use unsafe inappropriate construction methods and flammable materials. Flames recently spread across ‘flammable cladding’ in a fire at University of Bolton in the north west of England. The fire tore through a block of student apartments on November 15, 2019. It did so by “crawling up the cladding like it was nothing,” according to eyewitnesses. Some 40 fire vehicles and 200 firefighters were sent to tackle the blaze at the six-storey building. Flames poured from the windows on the top floors of a building known as The Cube on Bradshawgate, in the centre of the city.

The horrific Grenfell Tower fire in London in June 2017 and the 2014 fire at the Lacrosse apartment building in Melbourne’s Docklands in Australia, along with many others have highlighted the fire safety risks arising from the use of combustible cladding.

Insulating materials of the type blamed for the inexorable spread of the Grenfell Tower residential block fire in London are widely available in China and appear to be commonly used.

Foam insulation similar to that used on the exterior of the tower is both manufactured in China and used often by construction companies detailed in this site study. Inappropriate usage is a risk to life and property.

Polystyrene (PS) is a thermoplastic with a very poor reaction to fire properties (see Figure 1).

 

 

Figure 1. PS is a thermoplastic with very poor reaction to fire. Image displays poor unsafe site management of flammable materials

 

When it burns, a kilogram of PS will release more energy than a litre of petrol. Key characteristics of PS include: low cost, ease and speed of installation and its thermal insulating properties. PS is typically rendered with cement when used as a cladding material (see Figure 2).

 

 

Figure 2. PS cladding at the site study with a thin cement render

 

Chemical fire retardants may be added to PS but these do not prevent combustion from large fire sources. Furthermore, these retardants may leach over time.

In Miskolc, Hungary, in August 2009, three people died in a fire at a nine-storey block of apartments. The facade of the block of flats was renovated in 2007 and covered by an insulation system, consisting of 70mm-thick flame-retarded combustible polystyrene insulation with only a thin render on top, similar to as seen in Figure 2.

In April 2005, Berlin, two people died in an apartment when 80mm-thick EPS cladding on the exterior of the building caught fire, while a 1996 a fire at Düsseldorf Airport killed 17.

Australia: Major Public Safety Risk

In November 2017, an interim report found that systems failures have led to major public safety risks and widespread non-compliant use of aluminium composite panels (ACP) and expanded polystyrene (EPS) cladding in the building industry across Australia.

Inappropriate use of ACP (with polyethylene in its core) and EPS present a significant risk in Australia, and have been implicated directly in the Grenfell, Lacrosse and many other fires. In addition to being a fire hazard, both products are prone to melting, dripping and collapsing. When burning, polyethylene and polystyrene release two and a half times the amount of energy as an equivalent amount of timber.

As such, use of these products as external wall cladding presents a substantial risk to life and property, particularly in multi-storey buildings (see Figure 3).

 

 

Figure 3. Use of PS as an external wall cladding presents a substantial risk to life

 

Despite these risks, the author has found that buildings in Asia are still being constructed/renovated with inappropriate use of ACP and EPS. This article therefore recommends that governments take action to restrict the use of ACP and EPS in buildings above two storeys.

The European Fire Fighter Unions Alliance lobbied the EU on the subject, producing a score of examples where insulating materials had played a role in accelerating fires. About 500 million square meters of external facade insulation systems have been used to insulate buildings in Germany alone.

In future we will have more insulation in our homes and buildings, because of global environmental demands to save energy and CO2. A lot of that plastic insulation will accelerate fire spread, one reason being it is made of oil. The use of this oil-based insulation is held to be safe if it is covered by non-flammable casing or durable rendering, (see Figure 4). Moisture ingress to the newly fitted insulation at the study site will threaten the systems long-term integrity. However, extruded polystyrene (XPS) insulation, polyurethane foam insulation and expanded polystyrene (EPS) have been linked to disastrous fires in several locations since the late 1990s, according to firefighters.

 

 

Figure 4. The use of oil-based insulation is held to be ‘safe’ if it is covered by durable rendering. This image shows moisture ingress due to the new insulation in contact with the ground, thus accelerating degradation to the protective render

 

London: Grenfell Tower

Seventy-two people died in the blaze on June 14, 2017. ACP with a polyethylene core contributed to the fire load and the rapid spread of the fire up the vertical face of the high-rise building. In addition, the use of ACP cladding on the Grenfell Tower has been linked to the rapid spread of the fire around the outside of the building, alongside the chimney effect of the cavity between the wall and the cladding, and has been highlighted as a likely major contributor to the tragic loss of life in that incident.

Soil tests around Grenfell Tower have revealed toxins that could have health implications for local residents, according to early findings from a toxicology study. Professor Anna Stec (UCLAN), who conducted the study, is said to have found “huge concentrations” of potential carcinogens in the soil and dust around the west London tower block.

Fire History in China

Access to historic information and health and safety data is strictly controlled within the Peoples Republic of China (PRC). The information discussed in this article is based on a refurbishment site in China; a university campus home to 60,000 residents. Accommodation blocks (as shown) contain only a single exit, often blocked by charging e-bikes. The six/seven storey stairwells are not lit, there are no fire or smoke alarms at this site. Windows are covered with bars on the first two levels. There is a strict night-time curfew with a lights-out policy and locked gates to inner roads and areas hampering emergency vehicle access.

China has suffered fatal fire incidents in the past involving combustible cladding and insulation. Two intense fires which engulfed whole buildings demonstrate the potential dangers of combustible cladding and external insulation.

In September 2009, a fire in the CCTV Tower in Beijing killed a firefighter and caused €110 million worth of damage when it spread rapidly over sections covered by XPS insulation. In November 2010, in Shanghai, a fire in a building that was being renovated and externally clad in polyurethane foam left 58 people dead.

Television Cultural Centre, Beijing

Construction was started in 2004 and was expected to be completed in May 2009. On February 9, 2009, stray fireworks from Chinese New Year celebrations landed on the roof of the building, 31 storeys up, starting a fire which spread rapidly down to the lower floors, causing the death of a firefighter from toxic smoke inhalation and seven injuries. The whole 159m high building, topped out but still under construction, was ablaze at the height of the fire. Hard facts are difficult to find due to a news curfew, but insulating foam panels and polystyrene insulation have been implicated.

Apartment Building, Shanghai

On November 15, 2010 a 28-storey apartment building, which was under renovation, was consumed by fire. The 85m high building was fully scaffolded for the installation of energy-saving insulation when the fire occurred. Sparks from welding operations ignited construction materials incorrectly stored (as seen in Figure 1) and the nylon safety mesh on the outside of the building. Fire then spread rapidly along the scaffolding and through the interior of the block. Fifty-eight people lost their lives and 70 were hospitalised, including 17 who were seriously injured. Firefighters rescued more than 100 residents and others climbed down the scaffolding.

The fire was believed to have spread on polyurethane insulation to external walls. The fire may have been caused by the accidental ignition of polyurethane foam insulation, incorrectly stored on site, which commonly used in China without the addition of flame retardants.

Conclusions

The continual use of construction materials discussed in this article as external wall cladding presents a substantial risk to life and property, particularly in multi-storey buildings. Building construction codes across the world are being amended after consideration of recent events set out herewith. The use of combustible cladding is also a serious issue facing the PRC in 2020. This article recommends that action to restrict the use of ACP and EPS in buildings above two storeys are urgently implemented.

 

About the Author:

Professor Peter Hughes from England completed his PhD in material science at the University of Central Lancashire in 2013. He completed a post-doc research programme (ynthetics fibres in construction materials) in Japan in 2016. He has published papers on material science around the world and continues to contribute to various publications. He is currently based in China with university supervision roles in the UK, Ireland and Japan.