Why construction needs to know about pressure
17 Nov 2020
By Martin Kingsbury, Membership and Training Director at the British Fluid Power Association (BFPA)
The modern construction industry is reliant on fluid power. Hydraulic hoses are vital parts in almost every construction vehicle and numerous tools, from excavators and trucks to power and lifting tools.
But despite the central role of pressure systems in the day-to-day running of the sector, our industry experience is that few construction workers understand the real dangers presented by hoses, and the potential that cutting corners has for fatal injury.
It may sound unbelievable to some, but a pinhole sized leak in a hose can expel fluid at near-bullet speeds of more than 180 metres per second, depending on the pressure that it is under.
It is quite common for hydraulic fluid in construction use to be under pressure at 3000 PSI (207 Bar) and could range to as much as 6000 PSI (414 Bar). To put that in context, a typical car tyre is pressured at around 32 PSI and it only takes 100 PSI to puncture the skin.
Under high pressure, leaked fluid will puncture straight through protective clothing and pierce the skin – causing severe, life-changing fluid injection injuries (or fatality) from just one tiny looking pinprick.
Whilst you wouldn’t work with a loaded gun without considered and thorough training, there is a considerable gap in awareness amongst those working with hydraulic hoses.
Although such injuries only account for 1 in 600 hospital cases, over the 14 years running training courses at the British Fluid Power Association, I’ve met at least thirty people who have been affected by fluid injection injuries and it is often apparent when we shake hands and there’s a digit missing.
Many training participants can cite somebody they know who has either received such an injury and equally importantly, has had a near miss.
High pressure injection of fluid such as oil constitutes a medical emergency and requires rapid access to specialist surgical treatment. Prompt recognition of a fluid injection injury is essential to avoid fatalities.
It is critical therefore that those running sites and workers within construction have a full understanding of pressure systems they handle in order to keep safe on the ground. And by following best practice hose maintenance guidelines which focus on how to look after equipment, they can also enhance efficiency and productivity by reducing downtime.
Hoses can be damaged in many ways especially within construction operations which are hard environments. Within our training manuals, we’ve probably identified over twenty different ways that hoses can deteriorate – wear and tear, accidentally damaged onsite and mistreatment are just a few.
You could draw comparisons between hoses and car tyres. The rubber used will continue to cure over the course of its lifetime. It will be flexible when new and then slowly harden and become more brittle over time. Having an appreciation for how hoses can deteriorate is the first step to good maintenance and will potentially reduce hose failures.
Visual inspections are essential for good hose maintenance. Just as you would assess your car tyres by walking round the car and looking for bald patches on your tyres, the same principle applies to a hose inspection. Users can look to see if the hose is twisted, cracked from wear and tear, or is chaffing and rubbing. All these signs indicate that the hose is likely to require replacement.
Secondly, construction professionals should also make sure that they are using a hose supplier, distributer and fitter which carries the Q mark. The BFPA Approved Hose Assemblies Scheme and the associated Q ‘quality’ logo sets practice guidelines for hose manufacturing, distribution, and fitting – all of which come under ‘proper maintenance’.
Members of the scheme who sell and fit hoses under the Q mark must meet strict criteria to carry the accreditation, a sign of guaranteed quality.
The construction industry really needs to understand that whenever they invest in a hose assembly, they should only be buying from an approved company displaying that Q logo for peace of mind that they’re getting a quality product.
To qualify for the Q logo, members are audited. As part of my inspection visits, I’ll ask that members create a standard hose assembly, examine their paperwork and analyse the cutting and swaging processes. We check, amongst many other things, the vernier which measures hose collapse and that their swaging machinery is regularly calibrated and serviced.
We will also discuss the team’s training programme, checking that engineers, consultants and all staff have completed relevant training courses such as the ‘foundation course in working safely with hydraulic hose and connectors’ or ‘hose integrity, inspection and management’ to name but two of the five courses available from BFPA.
Members who supply hose assemblies also commit to never using unbranded hoses but specimens which carry the manufacturers trademark, cure date, size, type, working pressure and requirements of relevant hose standards.
You will never see a Q member re-work used hoses or crimped end fittings; they will always use hose end couplings which are designed to match the hose to be used; and will follow manufacturer’s crimping/swaging data implicitly.
If you opt for a hose distributor who does not belong to this industry standard, then equally, you cannot guarantee that they uphold their work to these strict standards. And it is these standards which ultimately ensure your productivity and safety.
Nigel Thomason, BFPDA chairman, recently said: “Choosing a supplier that carries the Q mark ensures efficiency. If you think about it, if your construction equipment is fitted with the correct hose, in the right way, by a highly qualified individual, it is simply less likely to fail. This means less downtime waiting for repairs, which in turn increases productivity and projects are completed faster.”
Having a clear understanding of pressure and in particular high-pressure systems, which are such a prevalent feature across the industry, means that not only do you comprehend the serious nature of these powerful systems, but that you are well equipped to improve on site efficiency and productivity by reducing downtime.