Build Back Better Part 3
MMC – A Safer & Healthier Way To Build
20 November 2020
At present, best estimates are that MMC equates for approximately 10% of UK construction with traditional construction at 90%. Savills also predicts usage of MMC for homes will rise to 20% in the next ten years. With Government endorsement of MMC through Homes England funding and predicted increases in its use, how can MMC contribute to a safer construction sector and healthier environments?
The construction sector accounts for approximately 7% of the UK workforce. The HSE also outlined in 2019, 79,000 workers were suffering from work-related ill health in the sector. Of these 62% related to musculoskeletal disorders, 21% related to stress, depression or anxiety, with the remaining 17% associated with other conditions. Regretfully there were 30 fatalities with 49% relating to falls from height, and 54,000 non-fatal injuries primarily resulting from slips, trips and falls and working at height.
MMC offers an opportunity to create safer working conditions through quality-controlled environments. Inherent with traditional construction are the common risks that cause accidents, injury and fatalities, including lifting and falls from height. Factory fabrication, whether on-site in flying factories or off-site in purpose designed facilities, involves specialist machinery, automation and appropriate tools and handling methods. An enhanced working environment is provided through control and sequencing, without having to factor in the weather.
The response to Covid-19 has the potential to further accelerate MMC use, given that factory conditions enable easier implementation and policing of social distancing with reduced numbers while maintaining high productivity levels. Modular units can be pre-fitted with services, window and door sets and fixtures and fittings, reducing the time spent onsite meaning risks can be more easily managed in one setting. Furthermore, there is opportunity to reduce the number of required trades on site and in doing so, decrease the need for scaffolding and manual handling.
The impact on the local environment for a construction site is also improved with reduced noise and air pollution, and reduction in waste when compared to traditional construction. These matters will have been addressed and resolved in the factory, resulting in enhanced environmental control measures and use of materials. Reductions in required vehicle movements will also typically reduce associated on-site risk, dependent on the complexity of installation on site. Some categories and material genres will also result in lighter construction systems when compared to traditional methods. This will lead to reductions in foundation depths, presenting opportunity for reductions in excavations and associated risk.
There are however variants of risk associated with different categories and material genres in the MMC Definition Framework, and site and project constraints will further increase these potential variants for suitable application. For example, increases in cranage time on site brings its own associated risk. The time a crane would be required on site for a 3D primary structural system (volumetric) is likely to be less than a 2D primary structural system (panellised) given the reduction in crane operations and constituent parts. Furthermore, construction of timber frame and mass timber do pose greater risk of fires on site during the construction phase, requiring mitigation. However, MMC generally presents potential for reductions in health and safety risks during the construction phase.
The benefits of MMC on health and wellbeing are not limited to construction. Utilising an enhanced fabric first approach with MMC as outlined in our previous piece MMC – A route to zero carbon, provides greater opportunity to achieve improved comfort when combined with suitable ventilation and moisture reduction, and overheating mitigation strategies. Furthermore, when combined with selected materials that limit the off-gassing of VOCs, indoor air quality can be greatly enhanced to the benefit of occupants. This will lead to decreased resultant respiratory conditions, leading to reduced strain on health services. When combined with access to open green space and exercise, MMC can contribute towards a healthier vision.
Covid-19 has focused minds on health, wellbeing and safety but has also provided focus on the resilience of the economy and adaptability of sectors such as construction to be able to respond. These must be at the heart of Building Back Better and MMC should represent an ever-increasing part of the solution.
– Paul Avery, Senior Architect