Why HS2 is using a different health and safety metric to most of the industry

HS2 Ltd’s latest board minutes reveal that a different health and safety metric is being applied during the construction of the country’s biggest infrastructure project, compared with standard models used across the industry.

HS2 Ltd claims its method of measuring accidents better reflects the actual situation on site.

Before major construction of the £107bn railway began in 2020, HS2 started using the Injury Weighted Index (IWI) to record the number of on-site accidents.

Unlike the Accident Frequency Rates (AFR) metric used widely by the industry, IWI measures both the incidence and severity of any incident, which HS2 claims creates a better picture of safety on site.

HS2 revealed the change of measure in its board minutes for its meeting in February.

“There is a revised approach being taken to the Health and Safety Performance Indicator (HSPI), moving away from AFR and towards the developed IWI, due to the increase in [the] threshold and nature of [the] work being undertaken,” the minutes read.

A spokesperson for the rail group said the “revised approach” was in comparison to the rest of the industry, rather than it being an approach newly adopted by HS2.

The scale of the project and the ramp-up of work means a different, more accurate picture of the incidents that took place is necessary, the spokesperson said.

It avoids situations where reporting just the number of incidents may paint the wrong picture of how the organisation’s contractors are performing when it comes to injuries.

Under the AFR metric, only the number of incidents is recorded, meaning that even though one month may have seen fewer incidents, some of them may have been much more serious and that would not be clear from the data.

However, under the IWI, accidents are given a score that depends on the severity of the accident. For example, a minor injury (such as a worker falling over in a car park) would be recorded as one, whereas any life-changing injury would appear as 1,000.

Contractors across HS2’s sites do not need to do anything to change their policies, as the rail group is responsible for adding up the number of injuries on site.

A spokesperson for HS2 said health and safety is “at the heart of our approach to construction”.

“The IWI, which we introduced early in the construction programme, adds a weighting for each accident reported across the project, giving us a clear view of not simply the number of incidents, but also of how each month compares in terms of severity,” they added. “This improves transparency, [and] helps us better recognise emerging trends across all our contractors’ sites and focus attention where it is most needed.”

In August 2021, HS2 Ltd called in the bosses of all the tier-one contractors working on the project due to concerns about an increase in accidents. But the rail group maintained that the increased number of accidents did not correspond to the 200 per cent rise in the amount of work.

In October, the Unite union claimed there had been a spate of serious injuries on sections of the HS2 line being delivered by the Skanska/Costain/Strabag joint venture.

Meanwhile, the Health and Safety Executive (HSE) announced in March that it would increase the number of inspections carried out in Birmingham in the coming months, as work is set to boom across projects, including HS2.

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