Distillery Safety - Facility design, process equipment, & regulatory compliance

I’ve considered writing again here and there for some time having given up on my old brewing blog five years ago when I moved to London to take the reins running the Sipsmith distillery. The thing is I didn’t really know what to actually write about that was worthwhile and that like-minded brewers or distillers would even be interested in reading?

I eventually came to the conclusion though that probably the most important subject I could discuss is safety. While it certainly isn’t as glamorous as marketing or as cuddly as culture it should be top of the priority list but often isn’t given enough consideration before getting into producing spirits. An understanding of compliance with legislation often takes a back seat rather than being fully investigated before construction is started and equipment is purchased, and even commissioning and operating. The thing about it is unlike every other direction you may choose to lead a business in, every avenue you wish to explore, compliance with health and safety legislation isn’t optional nor should it be guesswork. There is a legal as well as a moral obligation to meet certain well-defined standards for the wellbeing of staff, customers, contractors, neighbours, and the environment. Not to mention the risk to reputation and the fact that over 70% of businesses that suffer a catastrophic event such as a serious fire do not recover.

I'm going to focus on a topic that relates more to distilling, the regulations surrounding the operating of a hazardous facility storing flammable products, which are very similar in Europe, Australasia, and North America. The regulations are based on data and calculations, along with evidence and analysis of what has historically gone wrong, and with good reason apply irrespective of how small an operation might be. Even if it’s a few drums in a shed and a still off eBay it still counts!

In the US the main pieces of legislation distilleries must comply with is NFPA30:2018, and subsequent codes such as NFPA497 and NFPA499, that are best interpreted by DISCUS in their Recommended Fire Protection Practices. In Australasia there is AS/NZS1940:2017 and AS/NZS1962:2006, which you must pay for but there are guidance notes on the legislation downloadable for free from www.dmirs.wa.gov.au/ResourcesSafety. Finally in the UK where more sensibly you don’t have to pay to access the reports the main body of the legislation is covered by the Dangerous Substances and Explosive Atmosphere Regulations:2002, https://www.hse.gov.uk/pubns/books/l138.htm, along with further accompanying health and safety guidance including HSG176, HSG140 and HSG51.

These regulations define what is considered flammable liquid etc and stipulate all required aspects of handling & storage from overfill and spillage protection such as high-level probes and bunding; fabrication standards for vessels including material thicknesses and weld testing; mandatory documentation and inspection requirements; fire protection and safety shutdown systems; and ventilation requirements for storage areas and vessels. The most important thing after determining how much spirit will be on site and in what format is to tackle the zoning of hazardous areas surrounding flammable storage and what activities and materials cannot be in the vicinity as well as electrical and mechanical safety levels for equipment that is within those areas. The specific equipment standards can be found in IEC60079 and AS/ANZ67009 for the ATEx directives, and for the US in NFPA493 Standard for Intrinsically Safe Apparatus.

Possessing in excess of certain quantities may also make a site notifiable to the relevant authorities and require more stringent compliance, inspection and certification requirements. This is particularly important where bulk tanking by truck or ISO container is concerned as these usually put a site over the manifest threshold in a single load and require serious safety considerations such as the COMAH regulations in the UK. While usually around 10'000kg of alcohol, it is important to check your specific state as for instance this limit is just 120L in South Australia.

Hazardous areas are classified into zones based upon the frequency of the occurrence and duration of an explosive atmosphere. For a mixture with air of flammable substances in the form of gas, vapour or mist the zone classifications are 0, 1 and 2. The regulations also concern explosive atmospheres due to dust in installations where activities such preparing grit prior to mashing are carried out, which get the prefix 2 e.g. zone 2.1. The definitions of the zones are explained below:

• Zone 0 – An explosive atmosphere is present continuously or for long periods or frequently (~1000+ hours per annum).

• Zone 1 – An explosive atmosphere is likely to occur in normal operation occasionally (~10 to 1000 hours per annum).

• Zone 2 – An explosive atmosphere is not likely to occur in normal operation, and if it does for a short period only (< 10 hours per annum).

These zones change depending on a number of factors including rate of release; ventilation; design of the tank; the source of the release; the flashpoint and vapour density of the substance. Very basically though inside a still is considered zone 0, within 1.5m of any outlet or inlet is zone 1, extending 2m beyond them and any part of a vessel containing flammable liquid is zone 2 and, within 0.5m laterally & 1m vertically of the general containment area of a possible spillage is also zone 2. Inside any zoned area all sources of ignition including; naked flames, hot embers, smoking cigarettes, direct fired spaces and hot surfaces, mechanical and electrical devices, stray currents, electrostatic discharges, welding arcs and sparks from cutting equipment should be eliminated where possible and at a minimum identified and suitably controlled where allowed.

Effective measures include controls in place to prevent introduction of ignition sources, safe systems of work and contractor management protocols, safety monitoring and shutdown systems, and only using mechanical and electrical equipment made for the zone in which it is located. This means you may not be legally permitted to have a normal light fitting or electrical outlet next to a mill, or use equipment for transferring alcohol between two vessels that isn’t certified but you should certainly never have an ignition source like a naked flame next to a still. This last one was the root cause of a serious fire at a micro-distillery in the UK recently.

These zones can and should ideally be defined during the design phase of initial construction or modification to a distillery with a set of drawings produced in order to correctly determine the scope of works and specifications of required equipment prior to commencing of the purchasing process. They should also be on display for all visitors and staff when entering a hazardous area and be reviewed periodically along with risk assessments, standard operating procedures, and process and instrument diagrams.

While it might seem like just another hoop to jump through after TTB/ATO/HMRC approval along with everything else set out in a business plan, believe me doing this correctly at the start of a project is a lot less costly and painful than having to make amendments to civils, electricals or the pipework and vessels themselves later on when the focus should be on growth. If distillery operations isn't your field of expertise then I recommend engaging a consultant or hiring somebody who has a proven tack record in process engineering and managing safety to review your designs.