My last blog was on the costs of implementing functional safety. Those costs apply on the factory floor or for IC being developed for an automation safety system. But what about the costs of not implementing safety? The cost of not implementing the correct level of safety can include human health, human lives, increased insurance costs, loss of productivity, the failure of products in the market, environmental damage and within the EU at least, prison sentences. I didn’t title this blog the “cost of not implementing functional safety” as it is not always obvious if functional safety alone would have helped. A future blog will cover the differences between functional safety and normal occupational health and safety. For now let’s just say functional safety is only one aspect of the safety sphere.
As regards human health lets start with two studies, one from the USA and one from Ireland. The combination appears to show similar failures despite the different legal and regulatory environments.
First the data from the OSHA - 18,000 amputations or crushed fingers each year from workers operating or maintaining industrial machinery. The source is a blog available here where the author tries to answer the question as to whether safety can be justified as an ROI. OSHA has a safety pays website which according to the above blog calculates that the average crushing accident will cost a business an estimated $118k. These costs add up quickly and the 2019 Liberty mutual annual workplace safety index for the US says workplace injuries cost US companies over $1 billion per week including medical bills, wage and productivity losses. Note this includes construction, retail etc and not just manufacturing. I’ve seen a Colorado university study but don’t have a link to it on hand, which put the cost of workplace safety in the US at $128 billion/year.
An excellent Irish study on workplace accidents is available here and puts the average cost of injuries on the job at Euro 30k. It also discusses the cost to the employees.
As regards lost productivity, Control Engineering August 2017 states “In automobile manufacturing where a new car body comes down the assembly line every 60 or 90 seconds, downtime can cost original equipment manufacturers over $20k per minute” with a single incident costing millions of dollars. I am sure the figures for Power distribution and transmission would easily rack up similar societal costs if not more.
Rockwell Automation shows the productivity savings in these two videos
Before safe limited speed - https://www.youtube.com/watch?v=_mCnRVp_m9I
With safe limited speed - https://www.youtube.com/watch?v=AEh9QvqgNj4
And they are not the only ones to try and sell safety based on the costs of not having it as seen by the Schneider Triconex paper available here.
Rockwell in their excellent free book PROCESS SAFEBOOK 1 offers an example risk matrix which shows a comparison of the costs related to People, Assets, Environment and Regulation where they equate a single fatality per 1,000 years of operation to a major asset damage of $10 million, major environment damage or national impact on a companies reputation. You can argue over the details but the ALARP principle described in IEC 61508-6:2010 displays a means of calculating a figure up to which it cannot be justified to not spend more on safety and for that you must put a cost on a human life.
Of course, if your safety system is too trigger happy and trips all the time you can add a lot of cost due to those spurious trips and the resulting downtime and spoiled product. In these cases, architectures such as 2oo3 can be used to give high safety and availability.
Safety failures can even cost managers their bonuses as evidenced by this headline from an Irish newspaper.
Because the available studies include so many different business sectors perhaps it is more informative to study specific recent failures which have caught my eye.
The most obvious recent one is the Boeing 737 Max grounding. One article puts the cost at $4.9 billion with some papers claiming the problem is down to poor software techniques and with the software not taking advantage of the hardware redundancy available in the system. The applicable functional safety standards for Avionics include D0-178c for the software.
Several recent ones have related to Lithium Ion batteries whether in airplanes, in phones or robots. Kiwibots make a very nice looking food delivery robot but one caught fire on a public footpath in California in 2018. In a statement the company blamed the fire on “an exceedingly rare occurrence of the battery experiencing thermal runaway”. Relevant standards for a battery management system include IEC 61508 and ISO 26262. By the way Analog Devices makes some very nice lithium ion battery monitors in case anybody is suddenly worried.
Solar panels where standards such as IEC 61508, VDE4105, IEC 60730 could apply are not without problems either with articles such as this one stating that Walmart has asked Tesla to remove their solar panels from the roofs of Walmart stores due to several fires at Walmart stores.
To keep my software colleagues happy, I better include at least one software issue. I decided to pick the one related to claims of unintended acceleration of Toyota vehicles. Here the cost probably runs into billions. A report from the Barr group claims many weaknesses in the software and the potential for single bit errors in memories to cause issues. Being automotive ISO 26262 could apply but perhaps the developments predate ISO 26262 so that IEC 61508 could have been a choice to use for the developments to try and avoid the noted issues. However, I think IEC 61508 only added requirements for soft errors in the 2010 version.
Finally, I did mention that the costs could include prison time. The below is from an internal safety training presentation I use within Analog Devices. It outlines the penalties under the Irish version of the EUs General product safety regulations as including fines of up to Euro 3,000 and up to 3 months in prison.
So, not implementing safety might cost you dearly and the price for functional safety could easily be one worth paying.
For further reading on this topic I offer the following
“What went wrong-Case Histories of Plant disasters and how they could have been prevented” by Trevor Kletz looks good but it has been sitting on my shelf unread for a while now
See this UK page - https://www.britsafe.org/media/1569/the-business-benefits-health-and-safety-literature-review.pdf