It’s been nearly a year since Pyranha Mouldings Ltd. and Peter Mackereth, the firm’s technical director, were sentenced for corporate manslaughter following the death of an employee in a process oven. Alan Catterall was a supervisor for Pyranha Mouldings Ltd., a manufacturer of plastic kayaks and canoes in northwest England. Catterall, who entered the rotational molding oven to clear a fault, became trapped after a coworker switched it on. By design, the heating system, which was devised by Pyranha’s Peter Mackereth, closed automatically and locked with metal bolts on the outside. Though Catterall tried to escape using tools he had at hand, he was unable to attract the attention of his colleagues or gain his freedom. He suffered severe burns and died as a result of shock.

Following a trial at Liverpool Crown Court, the Royal Courts of Justice sentenced Peter Mackereth to nine months in prison suspended for two years. Both the company and Mackereth were fined. Mark Auty, senior specialist prosecutor with the Crown Prosecuting Service said in a release, “Mr. Catterall’s death was caused by the serious failings of his employer. By choosing to take on the design and installation of the machine, Pyranha Mouldings assumed responsibility for its safety. However, the machine clearly endangered the safety of those working with it, including Mr. Catterall.”

When I first joined Process Heatingmore than 20 years ago, I remember being (perhaps naively) shocked that processors sometimes chose to design and build their own ovens rather than work with a process oven manufacturer. The rationale offered at the time was that the engineering know-how existed at the company. Why shouldn’t they design it themselves?

I know that a strong do-it-yourself streak resides in many of us. I like to tinker and troubleshoot too. I remember shocking my mother when I took apart the lawnmower (and shocking her even more when I put it back together!). And while nothing is without risk, I believe every do-it-yourselfer has an obligation to those who could be affected by his or her engineering failures. So, build your own shelves and fail to anchor them? Likely, the worst that happens is that your books will fall, and you’ll have some drywall to repair. But, build an industrial oven for your facility? Every person that comes in contact with that equipment — perhaps in service for decades — is subject to any engineering faults in your design. That’s a higher bar and responsibility.

Regulations such as NFPA 86: Standard for Ovens and Furnaces, exist to help preclude these faults. NFPA 86 specifically addresses the “safe design; installation; operation; and inspection, testing and maintenance” of ovens and furnaces used for commercial and industrial processing of materials. An evolving document, NFPA 86 is updated every three years. The most current is 2015, and NFPA is accepting public input on the 2018 edition until June 29. (To comment, visit

Tempted to substitute your abilities for the collective knowledge of a seasoned industrial heat processing equipment manufacturer? Remember the fates of Peter Mackereth and Alan Catterall.