Isle of Harris Distillery
Isle of Harris Distillery
Tarbert, UK
About the Project
The Isle of Harris Distillery, located in the harsh coastal climate of the Outer Hebrides, upgraded its whisky maturation warehouses to comply with the Health and Safety Executive (HSE) guidelines and prevent rainwater ingress during stormy weather, which could compromise the internal environment and potentially damage the stored casks.
Challenge
This initiative was driven by safety concerns over ethanol vapour – a flammable substance released during whisky maturation, considered hazardous under the Control of Substances Hazardous to Health (COSHH) Regulations and the workplace exposure limits (WELs) outlined in EH40/2005.
As whisky matures, ethanol evaporates, with some escaping from barrels into the surrounding air. This process, known in the industry as the “angel’s share,” can lead to the accumulation of low-level ethanol vapours in enclosed spaces such as maturation warehouses. Due to the low flash point and high reactivity, ethanol poses a risk of ignition from static electricity or other potential ignition sources.
For whisky distilleries, this presents a dual challenge: maintaining ethanol concentrations within safe limits through adequate ventilation, while also protecting facilities from environmental factors.
The louvre system originally fitted in the warehouses proved inadequate, as it allowed significant amounts of rainwater to enter the facilities during storms.
In addition to providing reliable rain defence, the distillery required a solution that would allow for the manual closure of ventilation louvres during moor fires. These fires, commonly resulting from local farming practices, produce smoke and airborne particulates that could affect the quality of the maturing whisky if allowed to enter the warehouses.
Solution
Construction Specialties (CS) was engaged to propose a robust louvre system capable of withstanding the harsh coastal environment, ensuring effective air circulation and weather protection, while also allowing manual closure when necessary.
Following consultation with an independent Mechanical and Electrical (M&E) Consultant, it was agreed that the RSV-5700 louvre – with its vertical blade design providing both ventilation efficiency and weather resistance, as confirmed by independent testing to EN 13030 (Class A 3 up to 3.5 m/s) – would meet the specific needs of the site in line with regulatory requirements.
The proposed louvre model was tested on-site during the autumn and winter months, allowing the distillery to assess its performance under storm conditions. Initial tests revealed that, during intense weather, some rainwater collecting in the louvre’s cill pan could be blown back onto the warehouse floor.
To resolve this, CS collaborated with the estate and distillery managers to develop a modified cill pan featuring an extended, angled back plate and a slightly sloped base – unlike a typical flat detail – to promote more effective drainage and prevent water buildup. These modifications ensured a drier, more controlled environment even during severe storms.
A total of forty RSV-5700 louvres were supplied, each fitted with aluminium bird guards and the enhanced cill pan design. The units were powder-coated in Juniper Green (RAL 12B29) to complement the distillery’s aesthetic.
To meet the requirement for manual closure, heavy-duty toggle fixings were fitted at each corner of the louvres. This setup enables staff to quickly position and secure custom-fabricated steel sheets over the louvres during nearby moor fires. This bespoke solution provided the distillery with a practical, durable, and efficient method of protecting its maturation warehouses as needed.
