Waka Kotahi NZ Transport Agency has issued a technical advice note indicating its intention to move from hot cutback bitumen to bitumen emulsion products.

Civil Contractors NZ Technical Manager Stacy Goldsworthy said the change was positive and demonstrated Waka Kotahi's leadership to deliver better outcomes for workers handling and using bitumen in roading applications.

Mr Goldsworthy said hot cutback bitumen had a high associated risk due the presence of flammable vapours and the high temperatures at which it is applied to road surfaces. At the right percentage within a tank, the presence of kerosene in hot cutback bitumen creates a vapour that is highly flammable when an ignition source is present, and can lead to explosions. Heating the bitumen presents a significant risk of burn to workers during application. Bitumen emulsion represents a significantly lower risk profile with the removal of the explosion risk and the much lower temperatures used to heat the bitumen for application.

Other additional benefits of a change to bitumen emulsion is the wellbeing of workers working with the product. Hot cutback gives off kerosene fumes which if inhaled can have a significantly adverse effect on worker health.

“Those that handle emulsion understand the benefits to their well-being,” Mr Goldsworthy said. “Across the whole supply chain and maintenance  lifecycle, bitumen emulsion has demonstrable reduction in embodied carbon over hot cut back, primarily due to the reduced energy required to heat the product.”

Waka Kotahi has worked with the wider industry to understand risk to workers and look at the options to reduce the risk profile of sealing operations. The new technical advice note acknowledges that substituting bitumen emulsion reduces the reliance on the least effective administration and PPE controls that can be a significant part of current safe work practices for hot cut back bitumen.

CHASNZ General Manager H&S Innovation Jon Harper-Slade congratulated CCNZ on its advocacy for the change.

“Waka Kotahi have been making a positive difference to health and safety in the construction industry for some time now; this decision is another excellent example of their commitment to improving the safety of the work our people do across New Zealand every day,” he said.

Waka Kotahi’s move to the substitution of hot cut back bitumen with bitumen emulsion is in accordance with section 6(3)(a) of the Health and Safety at Work (General Risk and Workplace Management) Regulations 2016.
 
Further guidance on the safe use and management of bitumen is available on the WorkSafe website.
 
Note that this advice should not negate the use of other technologies or controls that provide a similar or lower risk profile. This will allow for continued innovation in bitumen application and further improve the health, safety and wellbeing of workers.