Non-compliant refrigerant leads to truck explosion

Windows and seal lying where ejected by the blast. Image: QMI

A cabin explosion has occurred while a mine worker was driving a truck in an underground mine in Queensland.

The accident, which took place last week (January 11), caused serious burns to the worker’s face, hands and chest.

His eyes were, however, protected from the blast by safety glasses.

The explosion originated in the truck’s air-conditioning (AC) unit, which was charged with a refrigerant containing propane and isobutane instead of complying with the original equipment manufacturer (OEM)’s requirement which specifies the use of R134a refrigerant.

According to the Queensland Mines Inspectorate, the AC was not certified for the use of the hydrocarbon refrigerant, adding that the personnel servicing the AC did not hold Queensland Gas Work licences for working with the refrigerant.

As a result, the release of hydrocarbon refrigerant from the AC into the cab created an explosive atmosphere which was ignited by an unidentified source.

Deformation of the metal filter access panel for the AC system. Image: QMI

 

Hydrocarbon refrigerants have a similar composition to LPG and are highly flammable, according to the Resources Safety & Health Queensland.

“A similar incident occurred in 2014 when a drill operator in a coal mine suffered burns to the face, hands and torso in an explosion after hydrocarbon refrigerant leaked from the AC system and ignited,” the inspectorate stated.

“… Investigations (into the latest accident) are ongoing and further information may be published as it becomes available.”

The inspectorate urged site senior executives to inspect all refrigeration plant and equipment including AC units on mobile plant to verify compliance with OEM guidance.

“Any refrigeration plant and equipment charged with refrigerant(s) not specified by the OEM must be immediately quarantined from use,” the inspectorate stated.

“If an alternate refrigerant is used, the refrigeration system must be inspected and certified for the use of that alternate refrigerant.”