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Safeguard OSH Solutions - Thomson Reuters

Safeguard OSH Solutions - Thomson Reuters


Best case scenario

JACKIE BROWN-HAYSOM visits a new plant which was the first to have its operating system approved under the HSW Act’s Major Hazard Facility regulations.

Being first off the block with a completely new way of doing things can be a struggle. With no examples to follow or cautionary tales to learn from, it can take a while to successfully match up theory and practice.

But at OnGas’s new Papakura facility – the first in the country to have its design and operating procedures signed off under the safety case requirements of the HSW (Major Hazard Facilities) Regulations 2016 – those involved with the development are fairly buzzing about what they’ve achieved.

“It’s been a widely collaborative exercise,” says Brenda Talacek, general manager gas trading for parent company, Vector. “We’ve really been struck by how much knowledge and expertise exists within our organisation, and how keen people have been to collaborate and help us build this.”

A safety case – something all new upper-tier major hazard facilities must now have – requires documentary evidence to satisfy WorkSafe that the facility operator has both the ability and means to control major incident hazards effectively. In short, it demonstrates everything has been anticipated and nothing left to chance, so any incidents that do occur will be successfully contained and minimised.

For a facility pioneering a new system for the refurbishment and refill of thousands of used barbecue gas bottles, using a workforce of new-hires, it was a tall order, but one that OnGas embraced. By the time the process was complete, in October 2017, the design features and product specifications addressed health and environmental risks as well as safety ones.

WORLD FIRST

The company previously used an external supplier to safety test and repaint used gas bottles prior to filling, but this had its drawbacks, so five years ago it began planning its own large capacity plant to handle all aspects of the process.

Everything that was to happen on site went through detailed risk assessment during the early planning stages so appropriate engineering controls could be incorporated into the design. Bottle swap business manager Craig Eagleton says the organisation worked closely from the start with Vector’s health and safety team, engineers from its Kapuni Gas Treatment plant, and Fire and Emergency NZ.

“We also brought in our environmental team, and operators from other similar facilities – both internal and external – to get their input on the design.”

What they came up with was a world first: a plant that uses a single-conveyor system to carry the bottles – including some from other suppliers with slightly different designs and weights – through a series of stations, where workers remove old labels, check for rust or damage, de-gas and decommission any that don’t meet the standard, and repaint, refill, and leak test the remainder.

Similar operations elsewhere in the world follow the previous OnGas model and outsource parts of this process, Eagleton says, but bringing everything onto one site has brought a host of benefits.

“We’ve got the best efficiency we could design in,” he says. “For instance, at the old plant a bottle that required the maximum amount of [refurbishment] work would need 21 manual lifts, but here we’ve been able to get that down to three.”

As a result of these efficiencies the plant will, when running at peak performance, be the sole OnGas refilling and refurbishment station for the country, supplying bottle swap facilities at 850+ retail outlets nationwide. To cope with this the new site has storage for 58,000 gas bottles, almost six times the capacity of the old plant, and will be able to process up to 6000 bottles a day in a single work shift.

“In the last two weeks of December around 60,000 cylinders were sold through our outlets, the majority of them from here, so that represents a lot of delivery vehicles moving on and off site,” Eagleton says.

DELIVERY PRECAUTIONS

On a site that feels like a small airport – with 20,000 square metres in concrete it requires its own stormwater management system – and holds tens of thousands of gas bottles, both full and empty, with constant forklift movements, it’s essential every visiting driver knows exactly what’s expected.

Before entry drivers conduct a walk-around fire safety check of their vehicles. Monitor cameras ensure this is done before the gate opens, and the driver hands in paperwork confirming there are no discernible faults that could cause fire.

Trucks loading and unloading cylinders follow marked routes to the parking bay, where the painted outline of a truck shows exactly where they must park.

“The trucks are curtain-siders, so the driver needs to be able to pull the curtains open and closed while the forklift is working,” Talacek says. “For this reason we’ve marked out a safe zone around the margins of the parking bay and divided it into boxes. The rule is that drivers must stay at least three boxes away from the forklift.”

For tankers delivering bulk LPG – the biggest single risk on site – the requirements are more rigorous, involving a combination of engineering controls and special operating procedures.

“We separate tankers from all other traffic,” Eagleton says. “They have their own site entry point, and we control access cards to ensure there is only one on site at a time.”

The route from gate to discharge point is clearly marked, and once there the vehicle must park inside a large water spray cage, which in an emergency can deliver 600 litres of water per square metre per minute.

Technology to ensure nothing goes wrong during discharge includes breakaway couplings which shut off supply if a truck moves away without disconnecting the LPG delivery hose, timers which prevent tank overfills, and an interlock that prevents LPG flowing until the tanker’s emergency shutdown system has been connected to the site one.

“If a driver hits the emergency stop, it will shut down the whole plant and, likewise, if we have a problem, our system will shut them down.”

Although there’s capacity to store nearly 200,000 litres of LPG on site, the above-ground storage tanks remain comparatively low-risk, Eagleton says, as they are technically viewed as mounded underground storage tanks. “The only vulnerable surface is the top, and we have a spray unit there to douse the tanks if there’s any risk.”

VISUAL AIDS

The processing plant itself looks rather like a large market building – no walls, and deep eaves spreading well beyond the work area. It’s unenclosed so small gas discharges will disperse harmlessly. The whole building is intrinsically safe, and Talacek says the 34 staff, most of whom are locals thanks to a recruitment drive that saw Eagleton handing out flyers on the street, have become used to “doing the haka” – patting themselves down before they leave the administration block to ensure keys, phones and other potential ignition sources don’t leave the office.

Inside the plant colour-coded overalls identify workers’ roles and levels of training.

“You can see at a glance who’s doing what, and who’s available to carry out a particular task,” Talacek says. “We use as many visual aids as possible, because it engages different senses.”

Colour coding is used in the wall-less work area as well, with the colour of machinery, and the lines marking out on the concrete floor, delineating areas where access is restricted.

When used bottles enter the plant those that need cleaning, repainting, or carry labels from other suppliers have their labels scraped off and are washed. Even this simple operation has been thought out: work tables are height-adjustable, the scrapers remove labels in a single stroke, and water used during the process is collected, filtered and recirculated.

If bottles have exceeded their 10-year safety certification any residual gas is recovered by suction and valves are mechanically removed, before trained inspectors check the interior for signs of corrosion.

Those unfit for further use are pierced using an enclosed mechanical punch which, like all machinery on site, is designed for failsafe operation. Its two control buttons can only be reached when standing clear, and interlocks prevent it functioning if the bottle valve is in place, or the punch lid insecure.

Skips for the reject bottles have been customised too, with a grille at the base to ensure remaining traces of heavier-than-air LPG do not pool at the bottom. Bottles suitable for continued use are stamped with a new test date and valves replaced, before joining an overhead conveyor to the paint shop.

LOW TECH & HIGH TECH

The painting process relies on the combination of a low-cost good idea – plastic cups over the conveyor hooks to keep paint off bottle valves – and a high-tech development – a new water-based paint that dries in only 10 minutes.

“Solvent-based paint was an issue for us because of both the fire risk and the occupational hygiene aspects,” Talacek says. The search for a solution ended when they heard Resene was developing a water-based product for shipping containers, and worked with them to come up with the right thing.

Painting is fully mechanised, the bottles rotating between spray nozzles inside a booth where the ventilation system is so powerful there’s barely a whiff of paint smell. The adjacent store, where paint is continually stirred and warmed to 30°C for optimal application, sits atop a large bund, with capacity to hold one-and-half times the volume of the largest paint tank.

Next stop for the bottles is a 20 minute spell in the drying room before heading to the refill station, where every bottle is automatically weighed and an operator keys in the empty weight so the filling machine can calculate the correct fill weight, and ensure every bottle receives the same amount of gas.

At the filling carousel high-tech once again blends with down-home solutions. As newly filled bottles move away from the automated filling station, an operator delivers a spray of soapy water onto the valve, looking for the bubbles that would indicate a leak.

It’s a tiny but important part of a design process that leaves nothing to chance.

A humble winner

In the multi-million dollar environment that is the new OnGas facility it is perhaps a little ironic that one of the more humble processes has been recognised with an award.

The pressurised spray wand, used to squirt soapy water onto the valves of newly refilled bottles to check for leaks, took out the health risk category last year.

The wand, now standard equipment at all OnGas LPG refill sites, has replaced the industry standard squeeze-trigger spray bottles, which, over time, put operators at risk of soft-tissue hand injuries.

It all began when Nakia Holland, a health and safety rep at the company’s Napier depot who had previously worked in the dairy industry, told management about the overhead pneumatic teat sprayers used to wash cows before milking.

If something similar could be used for leak testing, he suggested, it would remove the risk of hand injuries. The health and safety committee and company leadership team could both see the idea’s potential and Holland was asked for more information.

He provided the company’s engineering team with some design examples and a prototype was developed and trialled in Palmerston North.

Such was its success that the design was rapidly replicated and rolled out to all OnGas filling facilities across the country.

As a result reports of hand, wrist and elbow pain have dropped dramatically, and others in the industry are looking to introduce similar systems for themselves.

JACKIE BROWN-HAYSOM

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