BY RANDY BOGRAND, COO
Historians believe Greek warriors were the first to use armor, donning bronze plates on battlefields sometime around 1,400 BCE. Over the following centuries, civilizations around the world refined the practice, culminating in full suits of plate armor worn by soldiers in Medieval and Renaissance Europe. Ultimately, gunpowder rendered the traditional suit of armor useless. Soldiers now rely on high-tech materials like ceramic plates and Kevlar® to protect themselves in combat.
The history of armor is an excellent example of technology adapting to meet new circumstances. It is also an apt metaphor for the cold storage industry. Throughout history, armor has protected soldiers’ vital organs from swords, bullets, shrapnel, and other external threats. In many ways, a cold storage facility’s building envelope is like a suit of armor. It is a collection of independent pieces working together to protect the building’s contents from the threat of warm air infiltration.
In this new series, we will examine the individual components of a cold storage building envelope, including roof and insulation materials, vapor barriers, and more, to determine what makes the best building envelope. Like the knights of old, many cold storage operators may need to abandon their current practices and adopt superior methods to protect their operations.
Why is a Building Envelope so Important?
Cold storage operators have battled warm air infiltration for as long as there have been cold storage buildings. Keeping a building cold is relatively simple: turn the controls down until things start to freeze. However, unmitigated warm air infiltration creates significant problems in even the coldest buildings — namely, ice and condensation buildup and wasted energy.
The Threat of Vapor Drive
When warm air seeps into cold storage facilities through gaps in the building envelope, it rushes in to meet ice-cold air in a process called vapor drive. That collision of opposing air temperatures creates an environment where ice and condensation form. Historically, cold-storage operators saw ice and condensation as a cost of doing business. That view changed dramatically when the Food and Drug Administration (FDA) introduced new rules called the Food Safety Modernization Act (FSMA), designed to improve the safety of the country’s food supply.
FSMA Regulations: A Game Changer
The FDA had previously identified Listeria as a high-risk food contaminant that could cause widespread illness. FSMA requires food facilities “to have a food safety plan in place that includes an analysis of hazards and risk-based preventive controls to minimize or prevent the identified hazards.” The act also specifically addressed Listeria by identifying ice and condensation as contaminants that are not allowed in cold storage facilities. FSMA Final Rule § 117.20 (b) 4) states in part:
“(b) Plant construction and design. The… manufacturing, processing, packing, and holding… plant must:
4) Be constructed in such a manner that floors, walls, and ceilings may be adequately cleaned and kept clean and kept in good repair; that drip or condensate from fixtures, ducts, and pipes does not contaminate food, food-contact surfaces, or food-packaging materials;”
In simple terms, ice and condensation—proven to carry Listeria—are NOT allowed in cold storage facilities that store food. Failure to meet FSMA requirements could put cold-storage facilities at risk of severe penalties, including loss of USDA licenses and legal penalties. The integrity of a cold storage facility’s building envelope has suddenly become essential to ongoing operations.
Roofing Installation Practices Can Prevent Vapor Drive
The roof is, perhaps, one of the most critical components of a cold-storage facility’s building envelope suit of armor. Roofs do an excellent job of keeping water (snow, rain, hail, etc.) out of a building. However, they are deficient at stopping air infiltration. Every connection point between the roof deck and the wall is potentially an area where warm air can creep in and start causing ice and condensation. Here, we will compare the traditional method of roof installation with a technique that is more effective for cold storage environments.
The Traditional Roof Installation Method
Most cold storage buildings feature roofs that were installed the traditional way with four main components:
- Corrugated metal decking installed over steel joists or beams.
- Polyisocyanurate (PolyIso) or Extruded Polystyrene (XPS) roofing insulation, installed for an R-value of 35-50.
- An adhered thermoplastic polyolefin (TPO), polyvinyl chloride (PVC), or ethylene propylene diene terpolymer (EPDM) roofing membrane.
- A perimeter “vapor barrier” consisting of the roofing membrane and spray foam insulation applied in the roofing deck flutes.
Traditional roofing installation practices are insufficient for cold storage facilities for several reasons. For example, PolyIso insulation is inefficient against temperatures lower than 55 degrees and susceptible to moisture. If a roof failure or condensation buildup occurs, PolyIso’s R-value drops precipitously.
Additionally, adhered TPO and EPDM membranes have durability concerns. They can shrink over time, pulling away from seams and perimeters, potentially leading to leaks. TPO can deteriorate under high heat and UV exposure, while EPDM is vulnerable to oils and chemicals. Spray foam is also a poor vapor barrier. It is rigid and will inevitably separate from the deck flutes under natural building expansion and contraction. You can read more about our opinion of spray foam on the Vapor Armour blog.
In short, the traditional roof installation method leads to a building that does not hold temperature and will not keep ice and condensation from entering. Consequently, these methods are not FSMA compliant and can lead to food contamination in cold storage environments.
A Roof Installation Method Optimized for Cold-Storage
Departing from traditional roof installation methods enables us to create a building envelope that provides excellent insulation while preventing warm air infiltration. The elements of an effective roofing system include:
- Corrugated metal decking installed over steel joists or beams.
- XPS roofing insulation applied for an R-value of 35-50.
- A separate independent yet integrated vapor barrier around the perimeter of the building.
- A mechanically attached PVC roofing membrane on top of the vapor barrier but adhered to it and insulation.
In moderate climates, XPS insulation performs better than PolyIso insulation because its R-value improves as the mean temperature (the average between indoor and outdoor temperatures) drops below 75 degrees Fahrenheit. A vapor barrier applied around the building’s perimeter will prevent warm air infiltration, and a mechanically attached PVC roofing membrane will resist shrinkage and maintain its integrity over the long term.
This roof installation method will hold temperature, eradicate existing ice and condensation, and prevent it from reforming in the future. Cold storage facilities that utilize this installation method can ensure ongoing FSMA compliance while preventing dangerous Listeria contamination in their stored food products.
Case Study: Success in Illinois
Of course, installation costs play a considerable role in material decisions. For example, XPS insulation may cost as much as 20% more than PolyIso alternatives. That cost differential alone could raise the installation cost on an average-sized building by about $100,000. However, cold storage facilities with high-performing building envelopes operate much more efficiently than standard buildings. Consider the results from one Vapor Armour project in Illinois.
Pre-Installation Issues
This facility has severe icing and condensation problems affecting temperature maintenance. After conducting a forensic analysis, our team discovered that:
- Nearly 55% of the facility’s 90,000 sq. ft. negative 10° freezer had frozen insulation.
- 78% of the insulation in the facility’s 98,000 sq. ft. cooler was contaminated with moisture.
- All the insulation in the facility’s 18,000 sq. ft. 40° loading dock was contaminated with moisture.
Vapor Armour’s Installation Solution
Our team set out to fix the facility’s problems by replacing the contaminated insulation and installing a more effective vapor barrier featuring our Vapor Armour™ product. The installation process included,
- Removing all contaminated roof insulation and replacing it with XPS.
- Installing Vapor Armour™ vapor barrier to the facility’s freezer, cooler, and loading dock perimeters.
- Re-roofing the entire facility with PVC roofing membrane.
Project Delivers Significant Energy Savings
After completing the building envelope project, the Illinois facility saw tremendous energy savings that more than made up for the project’s $1.3 million cost.
- Energy Savings: The facility saw a 40% reduction in energy usage, representing yearly savings of $357,888.
- Payback Period: The facility’s return on investment was just under four years.
- Return on Cost: The project’s annual return on cost (ROC) was 26%.
Not only did this building envelope project make up for the added cost of premium materials through increased efficiency, but it also brought the facility into compliance with FSMA regulations.
Advanced Processes for Changing Needs
Just as gunpowder made traditional plate armor obsolete, new FSMA regulations force cold storage operators to adapt to a changing environment. It is no longer acceptable to work around ice and condensation; they must be eliminated. However, traditional roof installation methods simply will not prevent ice and condensation from forming. Therefore, operators cannot rely on them to maintain compliance with critical regulations.
Fortunately, Vapor Armour has outlined a roof installation method that is like Kevlar® against the onslaught of warm air. It seals the building envelope, improving operating efficiency, eliminating ice and condensation buildup, and bringing cold storage facilities into compliance with FSMA requirements.
Furthermore, our Illinois case study demonstrates that using superior materials correctly does not harm the bottom line. Instead, it boosts project ROI and drives continued energy savings for years after project completion.
Come Back for Part Two
In our next post, we will take a closer look at the materials involved in a traditional roof installation and compare them to those in our optimized installation process.
