"I accept Mr Waddell’s evidence that, had it been in good condition and operating in accordance with the specifications he found, the old pump should not have performed so poorly."

"Dr Casey conceded that, as long as everything else was identical, the results of Mr Waddell’s test supported the conclusion that the broken tap was a cause of the incident."

Court Case Extracts

Extracts from Judge Keogh J's comments in relation to evidence provided by expert witness civil engineer and ergonomist Mr Geoff Wadell.

Paragraph 6: Evidence was given by Mr Ford, and by three engineering experts, Mr Waddell for Mr Ford, Dr Culvenor for the Authority and Dr Casey for Snowy Monaro.

Paragraph 27: Dr Culvenor said the incident was caused by a mismatch of the pressure in the system and the clamps used to secure the fittings in the hose. Mr Waddell said the black plastic connector which fitted inside the hose was also potentially relevant to the incident.

Paragraph 34: Mr Waddell said it would have been better to use a metal connector, because the barbs in the plastic connector would have less ‘bite’ against the inside of the hose, and may deform under pressure.

Paragraph 50: Mr Waddell said according to the manufacturer’s specifications the old pump had a maximum pressure of 1120 kPa. After inspecting the old pump he said it was rusted and corroded and probably unserviceable. He said that if the casing around the impellers was corroded, the impellers were not spinning correctly because the motor was worn out, or the impellers or other parts associated with them were in a state of disrepair, there was likely to be a loss of both pressure and flow produced by the old pump. Mr Waddell said if the old pump was still operating according to the manufacturer’s specifications, it should have been delivering adequate pressure and flow. He said because it was no longer performing adequately, he had a strong suspicion the old pump had degraded over time.

Paragraph 53: I accept Dr Casey’s evidence that the number of impeller stages, and therefore the pressure the pump could achieve, is unknown and may have differed from the model specifications. The old pump was corroded. The internal workings, which have not been inspected, may have been in a state of disrepair, leading to reduced pressure and flow. For many years the old pump was performing poorly, especially when both wash bays were being used. I accept Mr Waddell’s evidence that, had it been in good condition and operating in accordance with the specifications he found, the old pump should not have performed so poorly.

Paragraph 57: Mr Waddell inspected the new pump and said that when it was running with no outlets open it registered 1100 kPa.

Paragraph 63: The experts each performed tests on site at the Saleyards in an attempt to better understand the cause of the incident. Mr Waddell used a length of hose and fittings which Mr Ford said were identical to those he was using when the incident happened. The fittings blew out of the hose three of the four times he tested the same procedure Mr Ford used when the incident occurred. He said the first test, when the hose and fittings were dry, most closely replicated the conditions of the incident. In that test the fittings blew off the hose after about 15 seconds, accompanied by a very loud and dramatic explosion.

Paragraph 69: The weight of the evidence from the expert tests is limited to some degree because the pump settings may have been changed between the incident and the testing. However, the results of Mr Waddell’s tests, particularly the first in which the fittings similarly exploded forcefully from the end of the hose when exposed to stagnation pressure, do provide some support for the conclusion I expressed in the previous paragraph.

Paragraph 77: In December 2013, Safe Work Australia produced the Guide for Managing Risks from High Pressure Water Jetting (‘the Guide’), which states that it applies to pumps with an output capability greater than 800 bar litres per minute, a measure of volumetric flow rate and pressure. Mr Waddell and Dr Casey were at odds as to whether the Guide applied to the wash bay system. Based on the pressure developed at the pump, Mr Waddell said that it did. Dr Casey measured outlet pressure and flow at the wash bay tap, and calculated the system had a capability of about 100 bar litres per minute. He said the Guide was intended to apply to washers, such as Kärcher, Gerni or Spitwater systems, in which water is compressed to very high pressures, and not to systems such as at that at the Saleyards. The Guide describes high pressure water jetting as ‘a process using a stream of pressurised water’, and states ‘common hazards and risks include the water jet piercing the skin’. I agree with Dr Casey that the Guide is intended to apply to washer systems operating at far higher pressure than the Saleyards wash bays.

Paragraph 90: Third, repairing the wash bay tap. Mr Ford submitted it was plainly negligent of Snowy Monaro to fail to maintain the components of the wash bay system. The tap was faulty for many years and should have been repaired. He submitted the following evidence established the broken tap was a direct cause of the incident. The incident happened on the first occasion after the new pump was installed that Mr Ford used the procedure of turning the pump on after placing the end of the hose inside a stock crate with the valve closed. Mr Waddell performed a test replicating Mr Ford’s procedure. In both the incident and the test the fittings blew out of the hose violently after about 15 seconds. Mr Waddell said it was likely the failure was caused by a ‘pressure pulse’. When Mr Waddell performed a test in which the tap was very slowly opened to allow a gradual increase in water flow, replicating the system Mr Ford used at other saleyards where the tap was not faulty, the fittings at the end of the hose remained in place. Dr Casey conceded that, as long as everything else was identical, the results of Mr Waddell’s test supported the conclusion that the broken tap was a cause of the incident. Mr Ford submitted causation was also established in a less direct way. Had the tap been working properly, he would have left the valve at the end of his hose partly open when he turned the pump on. Because the tap was broken he kept the valve closed, exposing the hose and fittings to stagnation pressure, which was a cause of the incident.

Full court report can be accessed via the Australasian Legal Institute -Ford v Elmore Haulage & Anor; VWA v Snowy Monaro.