A recent safety moment highlighted the dangers inherent in the simple domestic activity of gardening and the importance of wearing personal protective equipment (PPE), especially when using lawn mowers and strimmers. The guidance was to wear strong shoes and long trousers, not flip flops and shorts, to wear eye protection and to take time to clear the lawn of any loose stones, the danger being that these rotary devices can throw up stones at high speed, potentially causing either personal injury or physical damage. The warning was quite prescient as a week or so afterwards I heard about a strimmer throwing up a stone and breaking the glass in a French window.
But who wants to cut the lawn on a hot sunny day wearing long trousers and safety glasses? I have to admit that I do wear safety glasses when cutting the bush at the front of the house, despite being on show to all and sundry. Twigs, leaves and dust do indeed fly up and the glasses protect my eyes from any damage and subsequent irritation. Following the process of risk mitigation, the first question to ask is: can the risk be avoided? This could be a good excuse for not cutting the grass, but is unlikely to be acceptable. Protecting wildlife and helping the environment can justify deferring the first cut of the year, but there comes a time when it can no longer be delayed. So, we do need to take precautions such as removing obvious items that could be sent airborne, removing other people and animals from the vicinity and, finally, wearing PPE.
The challenge is to follow these steps in a domestic setting: having to go and get the PPE and needing to cut the lawn before it rains or the sport on the TV starts. Anyway, we have cut it many times before without any incident so we expect we can get away with it again. Two years ago, the lawn mower I was using kept cutting out because of a plastic mechanical cut-out on the switch. Knowing the electrical contact to be sound, I devised a way of operating the mower without it stopping until I decided I should not be tolerating this and bought a new mower.
Unfortunately, this is not an isolated example in either the domestic or industrial sphere. This article is headed ‘Tolerating defects’, but there is an official term for it: the ‘normalisation of deviance’. Although deviances in equipment and processes are accepted because experience persuades us that we can get away with them, they have culminated in a number of well-known disasters.
The loss of the Nimrod XV230 aircraft in September 2006, killing the 14 crew members, was attributed to an acceptance that leaks in fuel systems are a fact of life. Similarly, the Columbia space shuttle disaster in 2003 was blamed on the fact that foam strikes had become accepted as normal. More information on these incidents and the normalisation of deviance is provided at: https://humanfactors101.com/2016/08/09/normalisation-of-deviance. It makes for sobering reading.
I write this just after watching the BBC documentary Implosion: The Titanic Sub Disaster. If you have not seen it, then I would recommend you have a look on iPlayer. It is another example of warning signs being ignored and considered normal.
See also: www.bbc.co.uk/news/articles/c5yg5qggvwjo. Noise generated by delamination of the carbon fibre hull was picked up on acoustic emission sensors during Dive 80 in 2022. The sub imploded a year later in 2023. The real-time monitoring system installed on the submarine is described at: https://media.defense.gov/2024/Sep/25/2003553505/-1/-1/0/CG-107 NTSB TITAN MATERIAL ANALYSIS.PDF_REDACTED.PDF, which also provides the output from Dive 80 showing the emission event.
The official report will be issued later this year and it will be interesting to see what it says. However, the information provided so far highlights the role non-destructive testing (NDT) plays in safety and the importance of understanding the implications of the results obtained and acting on them. It is a shame that it takes tragedies like these to make us aware of the lessons to be learned and hopefully ensure that we implement them.
After a dry spring, any rain will stimulate the grass to grow, leading many of you to get out to cut the lawn. Keep safe!
Please note that the views expressed in this column are the author’s own personal ramblings for the purpose of encouraging discussion within NDT News. They do not represent the views of Amentum or BINDT.
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