Think about your national culture for a moment. I won’t risk exposing my prejudices by giving blasé (and probable trite) examples from other countries but will endeavour for my own. For me, British cultural concepts include Stoicism (the capacity to ‘grin and bear it’ whilst being diligent and respectable, as is exemplified in the slogan “keep calm and carry on”) and a particular type of humour (much British humour and sarcasm may be delivered through subtle or dry understatements). To this grouping I would also add the ALARP concept.

ALARP stands for “As Low As Reasonably Practicable“ and is derived from and encoded within English Case Law. The case in question is Edwards v. National Coal Board in 1949. Mr Edwards died in an accident after the supporting structure for the mine roadway gave way. The National Coal Board argued that it was too expensive to shore up every roadway in all of the mines. The case turned when it was decided that it was not 'all of the roadways' that needed shoring up; just the ones that required it. In essence this established the need to carry out a risk assessment to establish the cost, time and trouble to mitigate a risk balanced against the risk and the severity of any harm it might cause.

In his summing up, the judge stated “Reasonably practicable is a narrower term than ‘physically possible’ and implies that a computation must be made... in which the quantum of risk is placed in one scale and the sacrifice involved in the measures necessary for averting the risk (whether in time, trouble or money) is placed in the other and that, if it be shown that there is a great disproportion between them – the risk being insignificant in relation to the sacrifice – the person upon whom the obligation is imposed discharges the onus which is upon him.”

The UK HSE has used the ALARP Principle (that the residual risk shall be reduced as far as reasonably practicable), to successfully prosecute cases in recent decades. Examples include:

  • In 2017, a worker was crushed and broke 14 ribs when a forklift truck hit a pile of roof trusses which fell on him. The courts found that controls including safe methods of delivering work materials, training and suitable supervision could have prevented the accident. In 2018, a manufacturer was prosecuted and fined over £80,000 for failing to reduce risks ALARP.
  • In 2018 a steelwork contractor was fined £150,000 when a worker fell through a roof and fractured his spine. The courts found that alternative access equipment should have been provided to reduce the risk ALARP, and to avoid the need for the work to be carried out on the roof of the building.

In both cases, it is likely that there were measures in place to prevent cause becoming consequence (e.g. Fork Lift Truck driver training / licences or scaffolding erected to reach the roof). However, the judges deemed that they were not sufficient and that ALARP was not demonstrated.

I would argue that demonstrating a negative is challenging because this involves choosing additional steps which could have been taken (but were not), costing these and then working out by how much the risk has been reduced. A heuristic which I have encountered is ALARP is not demonstrated if Cost/year of Additional Safeguard <3x Risk Reduction Benefit per year. In this case the safeguard in question, should be or should have been implemented. Whereas, if the Cost/year of Additional Safeguard >10x Risk Reduction Benefit per year – ALARP is demonstrated and the safeguard is not required. The zone in between is left to company discretion.

So we have a template which we can apply. Great. But how do we decide which additional safeguard(s) to examine? And for how many scenarios? The time taken to demonstrate ALARP may itself not be ALARP! I encountered this dilemma a few years ago when I was undertaking a HAZOP at an explosives facility in the UK. The company had received a visit from an HSE inspector who found that there were several safety gaps. In his report, one of the recommendations was that they carry out a HAZOP of their facility and be able to demonstrate that any residual risks were ALARP. Accordingly, they signed up to an IChemE course which I was presenting, which led to them inviting me to start the HAZOP and develop a methodology which they could present to the HSE.

One of the key concerns identified by the inspection was that the preparation of the explosive chemicals was primarily a manual operation. During the exercise one of the participants said, a little ruefully, the inspector had unfavourably compared their process to one of a competitor, which he stated was ‘fully automated’, which reduced the residual risk associated with the manufacture. It struck me that this could be a good way of demonstrating ALARP in a holistic (as opposed to case by case, multiple scenario) basis. AKA the ALARP Anchor. The argument put to the HSE was as follows:

  • The residual risk of a fatality as a result of explosives production, following successful implementation of all the HAZOP recommendations = 2 x 10-4 / yr
  • Cost of a work place fatality = £5m (fines, loss of production, reputation etc)
  • Cost of fully automating the explosives production = £3m (or £100k / yr for a plant expected to run for 30 years)
  • The residual risk of a fatality as a result of explosives production, following successful implementation of all the HAZOP recommendations and production automation = 1 x 10-4 / yr
  • Risk reduction if ALARP step (automation) is taken = 1 x 10-5 / yr x £5m = £500 / yr
  • Cost of ALARP step is 100,000 / 500 = 200 times benefit gained. ALARP is demonstrated.

In conclusion, if you are responsible for the design or operation of a high hazard facility, you may  wish to consider casting off the ALARP Anchor to see if it reaches the sea bed. If nothing else, you should be able to sleep better.