Temporary Heating and Drying for Defence Sites

Temporary heating and drying on defence sites is rarely as simple as putting heaters into a cold building.

Aircraft hangars, vehicle workshops, stores and maintenance facilities are large, often draughty and subject to constant changes in temperature and humidity. They usually contain equipment that is expensive to repair and critical to operational readiness.

During the colder months these conditions become harder to manage. Doors are opened throughout the day to move aircraft, vehicles and equipment, permanent heating plant may be under maintenance or awaiting replacement, and many older buildings on the defence estate were never designed to hold stable conditions in every area.

In these situations, temporary heating, dehumidification and air distribution – together, temporary climate control – can maintain working conditions, protect valuable assets and keep maintenance and construction programmes on track while permanent systems are repaired, upgraded or not yet installed.

Why temperature and humidity both matter

Cold is the obvious problem, but temperature on its own is only part of the picture.

When warm, moist air meets a surface that is colder than its dew point, condensation forms. In a hangar or vehicle shed, that surface could be the steel structure, an airframe or a vehicle that has been outside overnight. Repeated wetting and drying over a winter can contribute to corrosion and deterioration of metalwork, electrical systems, avionics, tools, components and stored materials.

As a general guide, corrosion of steel is minimal at a relative humidity of around 50% or below. Above 60%, rust forms much faster as humidity climbs (see chart). That is why many equipment stores and preservation environments aim to keep humidity at or below 50%. The right target for any site should be agreed with the asset owner or equipment manufacturer.

The aim is therefore not simply to add heat, but to create and hold conditions that suit both the people working in the space and the assets being protected.

Heating alone may not solve the problem

One of the most common mistakes in cold, damp buildings is assuming that raising the temperature will fix the moisture problem. Heat lowers relative humidity for a while, but it does not remove water from the building. Once the heaters are turned down or the doors are opened, condensation can return.

The most effective solution usually combines three elements:

• Temporary heating to raise and hold the temperature. On defence sites, indirect oil-fired or electric heaters are generally preferred over direct-fired units, which release combustion gases and water vapour into the space.
• Dehumidification to actively remove moisture from the air. Desiccant dehumidifiers continue to perform well at low temperatures, making them well suited to unheated stores, hangars and winter drying.
• Air distribution using ducting and fans to move warm, dry air where it is needed. In tall buildings such as hangars, warm air rises and collects at roof level unless it is directed down to the working area.

The right combination depends on the building, the weather and the activity taking place inside. A large aircraft hangar with doors opening throughout the day has very different requirements from a sealed equipment store where holding a stable humidity level is the main priority.

Create a controlled zone rather than heating the whole building

Heating an entire hangar or warehouse to protect one work area might not be the most economic or effective path. It is usually more efficient to enclose the area that matters, using temporary screens or enclosures or an existing room and therefore create a smaller controlled environment where heat, humidity and airflow can be managed properly.

This approach reduces fuel and energy use, reaches target conditions faster and is less affected by doors opening elsewhere in the building.

During an aircraft hangar roof refurbishment at Bassingbourn Barracks, for example, low temperatures were slowing drying times beneath a temporary roof. Rather than heating the whole enclosure, the team needed to warm individual roof valleys to at least 5°C and rising. Diesel generators were not permitted on site, so RVT Group supplied three-phase electric heaters that worked from the available site power and delivered heat exactly where the work was taking place.

Supporting maintenance, refurbishment and construction

Temporary climate control is equally important when maintenance and construction schedules need to continue through winter.

Cold, damp conditions slow down engineering work and trades that are sensitive to temperature, such as painting and coatings, plastering and screeding. Manufacturers usually set a minimum temperature and maximum humidity for applying these materials.

Temporary heating and dehumidification keep work within specification and help dry out new and refurbished buildings before handover.

Temporary systems are also used during planned maintenance, plant replacement and unexpected heating failures, where waiting for a permanent repair would disrupt scheduled work.

Applications across defence 

Temporary heating and drying is used across the full range of defence environments:

Defence estates and infrastructure: barracks, accommodation, offices and community buildings during new-build, refurbishment, plant failures or periods needing extra heating or drying capacity.

Aerospace: aircraft hangars, engineering facilities and equipment stores, where large volumes and frequently opened doors make conditions difficult to control.

Maritime: dockside facilities, workshops, storage areas and maintenance operations exposed to damp, salt-laden air.

Land: vehicle maintenance facilities, workshops, depots and storage buildings affected by cold, condensation and changing humidity.

Defence projects RVT Group has supported 

• Weeton Barracks – heating and drying a modular building: a newly installed three-storey modular building, with 17 modules on each level, needed heating and drying across the whole structure rather than individual rooms.
• RAF Fairford – drying out for finishing works: drying support during taping, jointing and intumescent paint spraying at Douglas Bader House, linking climate control directly to finishing quality.
• RAF Lossiemouth – temporary electric fan heating: Climex^® heating kits to heat several project areas as winter approached, following an early site visit.
• Mons Barracks – temporary dehumidification: 96-litre dehumidifiers supplied at short notice to control moisture during MOD refurbishment works.
• RAF Digby and RAF Lakenheath – seasonal heating for live projects: temporary heating planned around the construction programme and available mains power, with hire periods running through the winter.

Planning a temporary heating and drying solution 

There is no single solution that suits every defence site. Before equipment is specified, it is important to understand the space and what the system needs to achieve. Key considerations include:

• Building size, height and construction, and whether the area can be enclosed
• Target temperature and relative humidity, and who sets them
• How often doors are opened, and for how long
• Sources of moisture, such as wet trades, washdown areas or new concrete
• Available power – mains supply, 415V/32A or 110V outlets – and whether generators or fuel are permitted
• Security and controlled access, which affect delivery windows, vehicle passes, escorted access and servicing
• How conditions will be monitored, for example with temperature and humidity data logging

This is why a site assessment should come before equipment selection.

A complete temporary climate control service 

RVT Group provides temporary climate control for defence sites, including indirect oil-fired heaters, electric heaters, temporary boilers, desiccant dehumidifiers and air distribution equipment. We support every stage, from consultation and site survey to delivery, installation, maintenance and removal.

For defence organisations, contractors and engineering teams, the aim is not just to provide temporary heat. It is to understand the conditions in the space, identify the risks to people, assets and planned work, and design a temporary solution around them.

By controlling temperature, humidity and air movement together, temporary climate control helps protect valuable assets, keep maintenance and construction on programme and maintain safe working conditions when the weather, or permanent building systems, cannot.

Book a free site assessment: call 0808 178 3286 or contact RVT Group.