Unitherm Insulation Systems

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The 7 Variables That Determine Pipe Freeze Risk

The Variables That Determine Pipe Freeze Risk

There isn’t one number that tells an engineer whether an industrial pipe needs freeze protection. Freeze risk is the result of several interacting design conditions, not a single ambient-temperature threshold — which is why a proper freeze protection design starts well before anyone selects equipment.

Heat-tracing manufacturers begin their freeze-protection design processes by establishing those conditions first. Here are the variables that matter most.

1. Minimum Ambient Temperature

The greater the difference between the desired pipe temperature and the surrounding temperature, the greater the potential heat loss. The appropriate design ambient should reflect the actual location and application, not a generic regional low.

Outdoor air temperature isn’t always the relevant number. Piping in unheated buildings or unconditioned spaces can be exposed to freezing conditions at different minimum ambient temperatures than what’s happening outside.

2. Desired Maintenance Temperature

Freeze protection doesn’t necessarily mean designing exactly to 32°F. Different fluids and processes can require different maintenance temperatures. Highly viscous fluids may need to be maintained above their freezing temperature simply to retain the viscosity necessary for flow.

3. Pipe Diameter

Pipe dimensions influence both the amount of fluid contained within the pipe and the thermal characteristics of the system. Freeze-time calculation and commercial heat-tracing design procedures account for pipe size, since a larger volume of fluid relative to surface area behaves differently than a smaller one.

4. Pipe Material

Thermon and nVent both include pipe material among the information required during heat-tracing design. The correct design should be based on the actual piping construction rather than assuming all pipes behave identically — different materials conduct heat at different rates.

5. Insulation

Insulation type and thickness directly affect heat loss. ASHRAE’s pipe-tracing heat-load calculation includes the dimensions and thermal properties of the insulation surrounding the system, since insulation slows heat loss rather than eliminating it.

6. Flow Conditions

A flowing system can behave very differently from a stagnant one. ASHRAE specifically notes that sufficient flow can prevent freezing, because the available heat content of the moving water offsets the system’s heat loss. Stagnant or low-flow sections don’t have that same continuous heat source, which is why they carry disproportionately higher freeze risk.

7. Equipment and Supports

Straight pipe isn’t the entire system. UniTherm’s design process requires designers to account for valves, pumps, other equipment, and pipe supports when determining heat-trace circuit lengths.

Evaluate Freeze Risk as a System, Not a Single Number

The lesson across all seven variables is the same: freeze risk should be evaluated as a thermal system, not from ambient temperature alone. Minimum ambient, maintenance temperature, pipe size and material, insulation, flow, and equipment all interact to determine how — and whether — a given line freezes.

UniTherm designs freeze protection around these actual operating conditions rather than a single temperature threshold. If you’re evaluating freeze risk for piping, tanks, or instrumentation on your site, contact our team to walk through the variables specific to your system.

This is week 3 of a 10 week series discussing the methods and science of frost protection systems. To learn more or to follow this series click this link: Subscribe to Updates

To find out more information on the frost protection offerings that Unitherm International can provide, go to shop.unitherm.com to view our full listing of products or email quote@unitherm.com to speak to a representative about custom insulation solutions.

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Freeze Protection: A Guide for Engineers and Maintenance Personnel

Freezing temperatures can create significant problems for industrial piping, valves, equipment, and the fluids moving through them. But effective freeze protection involves more than simply wrapping a pipe in insulation.

A properly designed system starts by understanding how heat moves from the fluid and piping system into the surrounding environment.

What Does Insulation Actually Do?

Thermal insulation limits heat transfer between a surface and its surroundings. In freeze-protection applications, this means slowing the rate at which heat leaves a warmer pipe, vessel, or piece of equipment and moves into colder ambient air.

While insulation does not generate heat, nor does it completely stop heat transfer. Insulation can extend the amount of time required for water to freeze. Prolonged exposure to cold temperatures can eventually freeze stagnant water even when the pipe is insulated, leading to cracks and bursts.

When Heat Is Required?

When natural fluid flow and/or insulation cannot provide adequate protection from freezing temperatures, it’s important to consider thermal heating methods.

One of the most common heating methods, and the method found in FreezePro insulation systems is heat tracing cable.

Traditionally Heat trace cable is wrapped around the pipe and secured with insulated blankets such as ceramic fiber blankets, however, FreezePro products combine the two for easy one step install.

The essential concept is that the two products are serving complementary functions;
the heat trace supplies the heat and the insulation retains the heat.

Regardless of how you choose to pair your heat trace and insulation combo, the essential concept is that the two products are serving complementary functions; the heat trace supplies the heat and the insulation retains the heat.

What Engineers Should Consider

Freeze protection isn’t as simple as the outdoor temperatures. There are many factors that can lead to frozen pipes and in turn, pipe damage. Here’s a list of a few thing any engineer should think about when creating a frost protection plan.

  • Pipe diameter
  • Pipe length
  • Pipe material
  • Minimum ambient temperature
  • Available electrical supply
  • Desired maintenance temperature
  • Startup temperature
  • Insulation type
  • Insulation thickness

Freeze Protection Is a System

The most useful way to approach freeze protection is therefore to look at the entire thermal system rather than one component. Engineers should consider the fluid, piping, equipment, insulation, environmental conditions, heat source when required, controls, and weather protection. When you understand the heat loss of a system you can then provide an adequate means of controlling it.

This is week 1 of a 10 week series discussing the methods and science of frost protection systems. To learn more or to follow this series click this link: Link

To find out more information on the frost protection offerings that Unitherm International can provide, go to shop.unitherm.com to view our full listing of products or email quote@unitherm.com to speak to a representative about custom insulation solutions.

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Building a 90-Day Process Heating Improvement Plan for Your Facility

Over the past twelve weeks, we’ve covered the fundamentals of process heating efficiency — from how energy is lost to how to make the financial case for improvements. This final post in the series offers a practical framework for putting those concepts into action over a 90-day window.

Unitherm recommends starting with a systems approach, identifying the components with the highest efficiency impact, analyzing those components in detail, and then implementing improvements in a sequence that accounts for how changes in one component affect others.

Days 1–30: Audit and Inventory

The first month is about understanding what you have. This means conducting a surface temperature survey of your process heating equipment using an infrared thermometer or thermal camera — noting which surfaces are running significantly above ambient. It also means documenting the insulation condition on pipes, valves, ductwork, and equipment: what’s insulated, what’s not, and what’s damaged or missing.

For fuel-fired systems, this is also the time to check exhaust gas oxygen content and verify that burners are operating at or near the target excess air level. A combustion analyzer can do this quickly.

The DOE’s Process Heating Assessment Tool (PHAST) is available as a free download through the Advanced Manufacturing Office and can help structure this assessment phase.

Days 31–60: Prioritize and Plan

With the audit data in hand, prioritize opportunities by two criteria: magnitude of the energy loss and ease of implementation. Insulation improvements on large, hot, uninsulated surfaces typically score well on both — significant energy impact, relatively straightforward to address.

For combustion adjustments, consult your equipment documentation and work with a qualified technician to verify setpoints before making changes.

For more complex improvements — waste heat recovery systems, burner upgrades, process controls — develop a project scope and get engineering input before committing resources.

Days 61–90: Implement and Measure

The third month is for acting on the highest-priority items and measuring results. For insulation improvements, that means ordering and installing covers, jackets, or blankets on the priority surfaces. For combustion adjustments, it means making the calibration changes and monitoring results.

Measure performance against baseline: energy use per unit of production before and after. Even simple tracking of monthly fuel or electricity consumption by system can reveal the impact of improvements.

UniTherm offers removable and reusable insulation solutions across the full range of surfaces identified in a process heating audit: plastics equipment (UniVest®), pipes and valves (IsoCovers), exhaust systems, and fire protection (FirePro). For a facility-wide insulation assessment, contact the UniTherm team at info@unitherm.com or 800.657.9542. We’re based in Lewisville, TX and serve facilities nationwide.

Keep Going After 90 Days

Each round of improvements creates a new baseline from which the next round of opportunities can be identified. Facilities that build efficiency review into their regular maintenance and operational planning consistently outperform those that treat it as a one-time project.

The resources referenced throughout this series — including the full DOE Sourcebook, tip sheets, and the PHAST tool — are available free through the Advanced Manufacturing Office at energy.gov/eere/amo. They’re worth keeping on hand.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

Source: U.S. DOE, Improving Process Heating System Performance: A Sourcebook for Industry (Third Edition), 2015.

This concludes our 13-week content series. For questions, insulation samples, or to discuss your facility’s needs, contact UniTherm at unitherm.com or 800.657.9542.

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Passive Fire Protection in Industrial Settings: What It Is and Why It Matters

Most industrial facilities think about fire protection in terms of active systems — sprinklers, suppression systems, and fire extinguishers. But there is another category of protection that operates differently: passive fire protection.

Where active fire protection responds after a fire starts, passive fire protection works by limiting the conditions that allow fire to spread. It doesn’t require activation — it’s built into the materials and configurations of the facility itself. For process industries that operate high-temperature equipment around combustible materials, passive protection is a critical component of a complete safety program.

What Passive Fire Protection Does

Passive fire protection systems are designed to contain fire and limit its spread by insulating ignition sources, protecting structural components from heat damage, and separating fire hazard areas from areas where personnel work. In industrial settings, this often means insulating hot components — pipes, valves, exhaust systems, and equipment — to prevent heat transfer to adjacent materials.

The thermal insulation function and the fire protection function overlap significantly. A cover that reduces heat loss from a high-temperature surface also reduces the risk that surface ignites adjacent materials or accelerates combustion in the event of an incident.

The Case for Passive Fire Protection in Industrial Settings

For components that require maintenance access — valves, flanges, pipe connections near combustible materials — rigid fire protection solutions create the same access problem as rigid thermal insulation. A removable flexible cover that provides fire protection allows inspection, maintenance, and repair without compromising the protection during normal operation.

UniTherm’s FirePro passive fire protection systems are flexible covers designed to insulate high-temperature industrial components and limit heat transfer in fire scenarios. They’re engineered for the access requirements of industrial environments — removable when needed, protective when in place. The FirePro line is available through shop.unitherm.com and information is at unitherm.com/passive-fire-protection.

When to Evaluate Your Passive Protection

Facilities should review passive fire protection any time there are changes to equipment layout, process temperatures, materials stored in the area, or regulatory requirements. Aging insulation that has lost its thermal or fire-protective properties should also be evaluated for replacement.

The combination of thermal insulation and passive fire protection in a single product is an economic efficiency argument as well as a safety argument — one investment serves two purposes.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

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Sustainability in Process Heating: What Manufacturers Need to Know in 2026

Sustainability has moved from a background consideration to a front-of-mind issue for manufacturers. Customers are asking about it. Regulators are requiring reporting on it. And the economic case for sustainable manufacturing practices is increasingly difficult to separate from the case for operational efficiency.

Sustainable manufacturing is the ability to continuously utilize resources to manufacture products and maintain the environment and our lifestyles indefinitely. Sustainability requires that our resources remain at their current levels or improve for future generations.

Why Process Heating Is Central to the Sustainability Conversation

Process heating accounts for roughly 61% of manufacturing on-site energy use in the U.S. It is also a significant source of combustion emissions — emissions are directly proportional to fuel consumption. Reducing energy use in process heating reduces the carbon footprint of manufacturing at scale.

The key sustainability metrics for manufacturing operations: volume of solid waste per unit of finished goods, energy input per unit of production, tons of carbon emissions per unit shipped, and gallons of waste water per unit shipped. Improving process heating efficiency directly improves the energy intensity and carbon emissions metrics.

The Role of Insulation in a Sustainability Program

Insulation is one of the most straightforward sustainability investments available to a manufacturing facility. Reducing surface heat loss reduces the energy input required per unit of production — directly improving energy intensity. And because emissions are tied to fuel use, less fuel means fewer emissions.

Insulation improvements that reduce energy use and emissions are a visible, documentable part of a sustainability program.

UniTherm’s removable and reusable insulation products support sustainability on two levels: they reduce energy consumption during use (lower heat loss = less fuel burned), and they’re reusable rather than disposable — which supports waste reduction goals. UniTherm’s products are engineered to last, reinstall cleanly, and be removed without generating waste. Visit unitherm.com to learn more.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

Source: U.S. DOE, Improving Process Heating System Performance: A Sourcebook for Industry (Third Edition), 2015.

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Making the Financial Case for Process Heating Efficiency Upgrades

Getting approval for efficiency improvements often requires more than an engineering argument. It requires a financial argument — one that connects the technical opportunity to the metrics that corporate decision-makers actually care about.

The most important thing to emphasize is that the corporate audience will respond more readily to a dollars-and-cents impact than to a discussion of energy use and efficiency ratios.

Start with Life-Cycle Cost Analysis

This approach captures the total costs and benefits of an investment over its service life — not just the upfront capital cost.

One of the key findings that often emerges from this analysis: for fuel-fired systems, fuel costs can represent as much as 90% or more of total life-cycle costs, while initial capital is only about 3% and maintenance about 1%. When fuel costs dominate the life-cycle picture, any measure that reduces fuel consumption — even a modest one — can produce significantly positive financial results.

The Simple Payback Calculation

For projects that produce consistent annual savings, simple payback is the most accessible starting point. It’s calculated as: Initial investment ÷ Annual benefit = Payback period in years.

For insulation improvements, the annual benefit is the reduction in annual fuel or energy costs resulting from reduced surface heat loss. The calculation requires an estimate of the current heat loss rate, the cost of the energy being lost, and the reduction in loss rate after the improvement is made.

Beyond Payback: Connecting Efficiency to Corporate Goals

Reduced fuel consumption lowers operational costs, which improves earnings. For publicly held companies, the sourcebook points out that improved earnings, multiplied by the price-to-earnings ratio, directly increases shareholder value.

Efficiency also reduces environmental compliance exposure: “Combustion emissions are directly related to fuel consumption. They rise and fall in tandem.” Better efficiency means lower emissions, which means reduced regulatory risk.

Worker safety and comfort are also legitimate benefits. Process heating system optimization yields safety and comfort benefits, in addition to fuel savings. Reduced surface temperatures from insulation improvements improve ambient conditions in work areas.

For removable insulation products, the financial case is often straightforward: the energy cost of an uninsulated surface running continuously at process temperatures can frequently justify the cost of the cover within months. UniTherm’s Energy Study Library documents results from real installations. Visit unitherm.com/media/energy-study-library.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

Source: U.S. DOE, Improving Process Heating System Performance: A Sourcebook for Industry (Third Edition), 2015.

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Preheating Combustion Air: A Proven Method for Reducing Fuel Use in Industrial Furnaces

For fuel-fired process heating systems operating at high temperatures, preheating combustion air is one of the most well-established and effective methods for reducing fuel consumption. The principle is simple: if the air entering the burner is already warm, less fuel is needed to achieve the required combustion temperature.

Combustion air preheating is the most commonly used method of waste heat recycling for high-temperature fuel-fired systems. It works by capturing heat from the hot exhaust gases and transferring it to the incoming combustion air — typically using a recuperator, regenerator, or heat pipe.

How the Savings Add Up

Combustion air represents a significant portion of the mass flowing through a furnace. Every degree of preheating reduces the fuel burden on the burner.

Depending on the system, exhaust gas temperature, and method of heat recycling, the sourcebook reports that it is possible to reduce energy intensity by 5% to 25% for heating systems. For systems with high exhaust temperatures, the upper range of that estimate is realistic.

When Preheating Is Most Applicable

For most fuel-based systems with relatively high exhaust temperatures — typically above 1,000°F — combustion air preheating is the natural first candidate for waste heat recycling. For processes using high volumes of air, such as drying ovens, preheating of makeup air or dilution air should also be considered.

For systems with lower exhaust temperatures or constrained configurations, other forms of waste heat management — including insulation improvements and load preheating — may offer better economics.

The Relationship to Insulation

It’s worth noting that combustion air preheating and insulation improvements are complementary, not competing. The sourcebook is explicit: tuning burners and improving insulation reduce the baseline energy consumption, which in turn reduces the magnitude of exhaust losses. Pursuing both together — reducing waste heat generation through insulation and recovering remaining exhaust heat through preheating — produces larger combined savings than either approach alone.

For exhaust systems and related components where heat management matters, UniTherm provides high-temperature insulation solutions for exhaust lines and associated hardware. Keeping exhaust temperature predictable and reducing incidental losses from exhaust piping supports the effectiveness of downstream heat recovery systems. Visit unitherm.com to learn more.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

Source: U.S. DOE, Improving Process Heating System Performance: A Sourcebook for Industry (Third Edition), 2015.

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What Is Waste Heat — And Can Your Facility Get Some of It Back?

Every industrial heating process produces waste heat. It’s unavoidable. The question is not whether it exists, but whether any of it can be put back to work.

Waste heat management covers three distinct activities: waste heat reduction, waste heat recycling, and waste heat recovery. Understanding the difference between these three is important for setting realistic expectations about what’s achievable.

The Three Categories

Waste heat reduction means reducing the generation of waste heat in the first place — through better insulation, tighter seals, lower exhaust temperatures, and reduced air infiltration. This is the category that overlaps directly with heat containment, and it’s generally the first step before pursuing recovery.

Waste heat recycling means using waste heat within the same system it came from. The most common example the sourcebook gives is preheating combustion air using heat recovered from the exhaust gases of the same burner. The sourcebook notes that this type of heat recycling can reduce energy use or energy intensity by as much as 25%.

Waste heat recovery means capturing waste heat from one process and using it in a different system — for example, using hot flue gases from a high-temperature process to generate steam or heat water for a lower-temperature process elsewhere in the facility. Payback periods typically ranging from one-half year to five years, with heat recovery of 10% to 75% of the available waste heat depending on the technology.

Where Waste Heat Comes From

The sourcebook provides a useful table of industrial waste heat sources and their temperature ranges. Furnace or heating system exhaust gases run between 600°F and 2,000°F. Gas turbine exhaust runs 900°F to 1,100°F. Hot surfaces — including uninsulated pipe and equipment surfaces — run between 150°F and 600°F. Even steam leaks and condensate return systems represent waste heat streams worth evaluating.

The Right Order of Operations

The sourcebook is explicit about the sequence: reduce waste heat first, then recycle it within the same system, then consider recovery to other systems. This matters because the economics of a heat recovery project depend on how much waste heat is actually available. Improving insulation and reducing air infiltration first may reduce the magnitude of the recovery opportunity — but it also reduces what the system has to generate in the first place, which is the better outcome.

Reducing hot surface losses through insulation is the first step in any waste heat management program. UniTherm’s removable insulation jackets, blankets, and covers help address heat loss from equipment surfaces, piping, and exhaust components — the foundational step before more complex recovery technologies are evaluated.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

Source: U.S. DOE, Improving Process Heating System Performance: A Sourcebook for Industry (Third Edition), 2015.

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Removable Pipe and Valve Insulation: Solving the Access Problem in Industrial Facilities

Every industrial facility has piping systems that carry hot fluids, steam, or gases. And most of those systems have lengths of pipe, valves, and flanges that are uninsulated — not because facility managers don’t understand the energy loss, but because traditional insulation creates a maintenance problem.

When you need to access a valve for inspection or repair, you have to remove whatever insulation is covering it. With hard insulation, that means cutting and disposing of material. The replacement costs time and money. Do it a few times and the insulation often just stays off.

Pipe and Component Insulation

The Department of Energy’s identifies poor insulation on piping and ductwork as a recognized source of energy loss. Surfaces such as piping and ductwork that have poor or no insulation are sources of energy loss that are “often overlooked” in process heating assessments.

This is common precisely because the losses are diffuse and continuous rather than dramatic. A valve loses heat quietly, hour after hour, day after day. The impact is real but easy to ignore.

What Removable Insulation Covers Actually Do

Removable insulation covers for valves, flanges, and pipe components are engineered to be installed and removed without tools or specialized labor. They’re typically made from high-temperature-rated materials, stitched or sealed to fit specific component configurations, and secured with straps, lacing, or fasteners that allow for quick removal.

The key advantage over traditional insulation is that the covers are designed from the start to be removed and reinstalled. The insulation material doesn’t get damaged in the process, so the cover remains effective after repeated use.

UniTherm’s IsoCovers are removable insulation covers for valves and flanges. They’re available in standard sizes through the UniTherm shop and can be custom-manufactured for non-standard component configurations. Visit unitherm.com/pipe-and-components for the full range, or contact UniTherm to discuss a custom solution for your system.

Industries That Use Them

Removable pipe and valve insulation is used in oil and gas, power generation, chemical processing, food processing, marine applications, and anywhere else that high-temperature piping systems require regular maintenance access. The ROI case is generally straightforward: the energy cost of an uninsulated valve running continuously at operating temperature is often large enough to recover the cost of the cover within a single heating season.

For facilities in cold climates, there’s an additional benefit: reducing surface heat loss can help maintain consistent process temperatures in areas where ambient conditions vary seasonally.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

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Insulating Plastics Processing Equipment: How to Really Cut Your Facility’s Costs.

Plastics processing equipment, injection molding machines, extruders, blow molding equipment — operate at sustained high temperatures. The heating zones along a barrel or nozzle are running continuously, and a significant portion of that heat radiates outward into the surrounding work area rather than staying in the process where it belongs.

This is a straightforward heat containment problem of the kind identified in the DOE’s process heating sourcebook, and it has a straightforward solution: insulating plastic processing equipment keeps the heat in the barrel and out of the shop floor.

What’s Actually Happening Without Insulation

An uninsulated barrel on a plastics processing machine loses heat through radiation and convection from its surface. The control system compensates by running the heaters longer or more frequently to maintain the set temperature. More heater activity means more energy consumed, more wear on heating elements, and a warmer ambient environment around the machine.

The DOE sourcebook notes that improving insulation on process heating equipment reduces the amount of energy needed to perform a given heating task, reduces thermal stress on system components, and can improve consistency and product quality. All three of those benefits apply to plastics processing equipment.

The Case for Removable Insulation on Barrels and Nozzles

Permanent insulation on a plastics processing barrel is impractical. Operators need access to heating zones for inspection, thermocouple replacement, and maintenance. Fixed insulation that has to be cut away and replaced every time someone needs to check a heater band is not a workable solution.

Removable insulation jackets address this directly. They’re designed to fit specific equipment configurations, attach securely during production, and come off quickly when access is needed. The insulation itself is protected from damage during removal, so it can be reinstalled and reused.

UniTherm’s UniVest® insulation jackets are designed specifically for plastics processing equipment — barrels, nozzles, dies, and related components. They’re engineered for the temperature ranges and access requirements typical of injection molding, extrusion, and blow molding operations. Available through the UniTherm shop at shop.unitherm.com.

What to Expect in Terms of Results

While results vary by equipment type, temperature setpoint, and ambient conditions, published energy studies have documented meaningful reductions in heater band energy consumption when insulation jackets are added to plastics processing equipment. In addition to direct energy savings, facilities often report reduced ambient heat in work areas around the machines — a worker comfort and safety benefit that the DOE sourcebook also identifies as a legitimate benefit of insulation improvements.

UniTherm maintains an Energy Study Library on its website with documented results from insulation applications. Visit unitherm.com/media/energy-study-library for case data.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

Source: U.S. DOE, Improving Process Heating System Performance: A Sourcebook for Industry (Third Edition), 2015.

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UniTherm Insulation Systems

711 Jones St.
Lewisville, TX 75057
Toll Free: 800.657.9542
Phone: 972.436.1401
Fax: 972.436.0112
info@unitherm.com