The growth in cold chain logistics has been accelerated as more customers turn to online grocery deliveries.

Specialists in temperature-controlled warehouse spaces have had to respond to clients’ needs for technical solutions to meet this increased demand. This expertise has, in turn, helped those clients ensure the flexibility they need to satisfy their customers.

Now analysts predict habits formed during the lockdown forced by Covid-19 will continue as social distancing is eased further.

In the UK, the Office for National Statistics reported that while goods sold were down 18.1 % in April, online shopping as a proportion of all retail hit a record high of 30.7%. And, perhaps most significantly, the proportion of online spending on food increased from 5.7% to 9.3%*

Customers working from home, or prevented from doing routine shopping, have enjoyed new retail experiences such as doorstep deliveries of recipe boxes packed with fresh produce. And it is likely they will want more.

It’s a challenging environment, but one in which agile, high-tech operators can not only survive . . . but thrive.
Let’s take a look.


Coronavirus may be reinforcing industry trends but GLP has already provided more than 300,000 square metres of build-to-suit chilled units around the world. Why is that important? Well, the design of a temperature-controlled warehouse can have a disproportionate effect on long-term capital cost and operating bills. So it is important to try to guarantee cost-effective integration between technology and operational targets.


Shoppers expecting to scroll down a shopping list and have an out-of-season artichoke delivered in 24 hours are helping to boost an already burgeoning market.

That means logistics firms have to provide increasingly complex storage and supply chain technology to help clients cope with the spike in demand for fresh and frozen produce.

“I see Covid-19 as a major industrial revolution in logistics,” says Graeme Munro, GLP’s Head of Construction in Europe.

“The landscape of logistics is changing, driven by consumer behaviour. E-commerce is driving everything and every company is strategizing to have a supply chain that can manage it.”

FROM -30 ° C TO 25 ° C

A cold chain can be broadly defined as the systems, equipment and logistics necessary to maintain a product hygienically within a low temperature range from harvest or production to consumption. It preserves the integrity of products, extends their shelf life and reduces waste.

Temperatures are often described as:

Ambient 15 to 25 ° C (for products such as tinned goods)
Chilled 0 to 8 ° C (ready to eat sandwiches, dairy products, fresh meat)
Chilled -1 to -30 ° C (frozen foods)

But it is increasingly a more complicated and nuanced picture. “Cold chain logistics is complex because you have a lot of different temperatures to deal with,” says Graeme Munro. “An egg storage or processing facility may require temperature chambers of 16 ° C, whereas meat and poultry only need 1 ° C. You’ve got to go to -30 ° C for frozen goods so it covers a huge window.

“We need to know what the customer’s product is. For example, you can’t leave chocolate at below 12 ° C. You want it sitting at about 12 ° C to 16 ° C for optimum quality. Otherwise it goes white. It needs a bit of heat in the winter and a bit of cooling in the summer.”

The challenge is made harder by the variety of customers who each bring with them their own processes. “You’ve got to have the facilities to flex to today’s market,” says Graeme. “Supermarkets like Lidl, for example, require five or six different levels of temperature for their products.”

That’s why more detailed guides of optimum temperatures can look like this:

Time is also an important consideration. Refrigerated requirements vary from long-term frozen storage and blast freezing to fast-moving chilled picking facilities. Storage is often categorized as short-term (less than a week), medium-term (1 to 4 weeks) and long-term (4 weeks to 12 months). Temperature and atmosphere become more critical as storage duration increases.

Meanwhile, some fruit and vegetables “respire”, releasing ethylene and CO2 as they ripen. They require specialist ventilation. Strict compartmentation is also key to preventing one product’s odour tainting another. After all, nobody wants asparagus that smells of onions…


Global leaders in the industry can have a portfolio of units ready for conversion to refrigerated use – but also provide bespoke solutions for more complex challenges. And, at the end of a lease, they can often facilitate a simple reversion to an ambient operation.
Refrigerated facilities need to be insulated to high standards to reduce heat gain and air infiltration and, in turn, reduce plant size and costs.

There are broadly two approaches that can be taken.

1. Install an “insulated envelope” in an existing ambient warehouse, often called a “box-in-a-box”. Outstanding ATTMA Air Permeability ratings of <0.2m3/h.m2 @ 50Pa are achievable. If sub-zero freezer chambers are required, heater mats and sub-floors are often deployed to ensure insulation. This solution enables fast track delivery of most requirements.

2. Enhance insulation of the whole building to form a “single envelope”. This is a bespoke project.

Single Envelope:

The Single Envelope design utilises an internal structure and specialist composite
insulation sandwich panels installed exterior to the structure, to form a fully vapour
sealed and insulated enclosure. The design requires a two pitched roof with external
gutters in order to provide a fully insulated and vapour sealed enclosure:


The Box-in-Box design utilises an internal structure which is externally clad using
‘standard’ ambient cladding panels (both roof and walls). A specialist internal
insulation envelope is then installed within the structure to form the refrigerated

Both solutions have pros and cons which must be balanced against clients’ requirements.


GLP is committed to “natural refrigerants” such as ammonia and CO2 which offer high efficiency with the bonus of minimal global impact.

Ammonia and CO2 have zero Ozone Depletion Potential and a Global Warming Potential (GWP) of zero and one respectively.

This emphasis on carbon footprint is important because the heart of a temperature-controlled facility is the refrigeration plant and it can represent 80% of energy consumption.

Our “off the shelf” refrigerated fit-out enables the speedy implementation of green refrigerants but we strive to offer solutions designed to flex and meet future legislation and standards.

That means we offer a menu of extra eco-initiatives. They include:
• Waste heat recovery – re-using for heating and hot water.
• Chemical-free water treatment for evaporative condensers.
• Reverse osmosis – recycling waste condenser water.
• Hybrid condensers – enabling water reduction.
• Combined Heat and Power in conjunction with absorption plants – generating power on-site and using waste heat to drive the refrigeration plant.
• Thermal batteries in conjunction with solar photovoltaic cells – enabling thermal battery “charging” during the day, to facilitate “off-grid” refrigeration at night.
• Use of refrigeration plant to air-condition offices (ensuring only natural refrigerants on site).


Ironically, sub-zero facilities need insulated and heated sub floors to prevent frost heave. Underfloor heating can use electricity, pumped glycol or forced air. Some warehouse spaces are built with up to six layers of flooring. So the finished floor sits on top of insulation, a vapour barrier, screed, a heater mat and, finally, the warehouse floor itself.

Cold store floor slabs are monitored during the critical initial temperature pulldown. Too fast a process can result in cracking. Particular attention is paid to expansion joints.

Floor technology is particularly important to GLP because as a leading developer, investor-owner and manager of logistics real estate, we let many of the buildings we construct.

“If you were an owner occupier, you would probably go into the floor, because it’s your slab,” says Graeme Munro.

“But because we let the buildings, we don’t want to put more load into the floor of something that might not be a freezer in 10 years’ time. So we build above the slab with an insulated floor, creating the box within a box.

“Our baseline specification has to be able to flex in any direction for any customer. That’s the benefit of what we can offer.

“We’re able to facilitate a turnkey design and effortless process for them. They know their process. We know how to build a warehouse. But we bring it all together.”

Indeed Graeme’s team has just issued a “layman’s guide”.

“We can have a cold room box ready that flexes to all needs,” he says. “We have developed a design guide that spells out in layman’s terms how you build a refrigeration plant and how you deliver it within any programme for any temperature. We can take a generic size for any country’s market and flex it. We can take away the pain of the process for customers.”


GLP believes the pressures of coronavirus have underlined the importance of flexible relationships between businesses.

“You’ve got to integrate your process with their process,” says Graeme. “It’s always evolving. They learn from you and you learn from them. Every building we’ve built we’ve learned something about the customer’s side, something that maybe we didn’t appreciate about exactly what they need. So, there’s always a bit of a hand-holding exercise between the two.”


We have delivered more than 393,000 square metres of build to suit projects for chilled unit specifications.


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