20 August 2013

Early thinking about work health and safety helps reduce risk

RMIT researchers are examining the potential benefits of addressing work health and safety (WHS) before a construction project starts.

It is often argued that opportunities to reduce work health and safety (WHS) risk are highest at the beginning of a construction project and become fewer as the work progresses.

By the construction stage, the opportunity to eliminate or ‘design out’ hazards may be limited. This is expressed in a time/safety influence curve, depicted in the Szymberski image (below).

This curve is almost universally cited by advocates of Safety in Design but until recently, little empirical evidence was available to support it.

The research explored the validity of the time-safety influence curve by examining the relationship between the timing of WHS risk control decisions and the quality of implemented WHS risk control solutions.

During the course of the research, data were collected from 23 construction projects, 10 of which were in Australia/New Zealand and 13 of which were in the United States of America. A total of 288 interviews were conducted (185 in Australia and 103 in the USA).

Comprehensive data was collected from each project. This data captured decisions made in relation to specific features of buildings/facilities, the process by which these features were constructed and the way that WHS hazards were addressed.

Key decision points through the life of the construction project (including during the planning and design stages) were mapped and the precise timing of decisions about how to control a WHS risk was identified for each work feature.

A score was generated reflecting the quality of risk control solutions implemented for each feature.

This score was based on the ‘hierarchy of risk control.’ Thus, a high score reflected the implementation of technological risk controls (such as elimination, substitution or engineering), while a low score reflected the use of behavioural controls (such as administrative measures of personal protective equipment).

Australian projects had significantly higher average “hierarchy of control” scores than US cases.

A significant positive relationship was found between deciding how to address a WHS hazard in the early stages of a construction project and the eventual implementation of higher order (i.e, technological) risk controls in the construction stage.

The results indicate that it is statistically more likely that technological risk controls (i.e, elimination, substitution and engineering controls) will be implemented if WHS is considered in the pre-construction stages of a project and risk control decisions are taken in these early stages.

Assuming that technological risk controls will have a greater risk reduction effect, our results support the notion that the ability to influence safety would be substantially lower if consideration of WHS (and selection of risk controls) was left until the construction stage had commenced.

The research provides preliminary empirical evidence to support the time/safety influence curve in the construction industry.

*This is an abridged version of a full paper submitted to Engineering, Construction and Architectural Management.

*This work was supported by Cooperative Agreement Number U60 OH009761, under which RMIT is a subcontractor to Virginia Tech, from the US Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the CDC NIOSH.*

More news from the Centre for Construction Work Health and Safety

The time/safety influence curve (adapted from Szymberski, 1997)

The time/safety influence curve (adapted from Szymberski, 1997), Szymberski, R., (1997), Construction Project Safety Planning, TAPPI Journal 80 (11) 69–74.