In most parts of the country, there is a period of the year when ambient temperatures fall below the minimum recommended storage temperatures for your polyurethane chemicals. In these conditions applicators can run into problems keeping their chemicals at recommended storage temperatures of 70° – 85° F. Some polyurethane systems are more sensitive to pressure and temperature settings than others. If the applicator’s chemicals are a little on the cool side and their equipment is not able to raise the temperature of the chemicals to recommended application temperatures, the applicators can experience poor mixing at the gun and poor polyurethane quality.
As the weather begins to cool, we recommend contractors review their procedures to avoid problems which can be directly attributed to lower temperatures.
Keep Your Material Warm
Material storage issues are the most common causes for problems in cold weather foam application. Using material that has dropped below 70°F can cause cavitation in the proportioner, off-ratio foam production, and loss of yield.
If chemicals are slightly too cold, the options are:
Gradually warming the chemicals up to recommended storage temperatures is the best option. Just as it takes some time to cool off 55 gallons of material, it takes some time to warm up 55 gallons of material. The problem with trying to heat the material up too fast with jet burners and band heaters is you run the risk of boiling the chemicals, pressurizing the containers, and making it very difficult to open the drums to insert your drum pump.
As a rule of thumb, it is always more efficient to maintain your chemical storage area at a constant temperature rather than letting the material get cold and trying to warm up the material prior to application. If you have a large warehouse space and don’t want to pay to heat all the space, build a storage area within the space that can be heated separately.
Using heaters in the rig overnight is a good idea, just make sure you are not creating a fire hazard by not using the right equipment. Space heaters need to be in good condition and not powered by liquid or gas fuel. There are diesel heaters that can pull fuel from your tank, these are fine if properly installed.
Colder Temperatures Reduce Yield
Cold ambient temperatures and substrate temperatures rob the heat of reaction from the foam upon application. Higher densities translate into lower yield, sometimes significantly lower yields.
Do Not Recirculate
NCFI does not recommend using re-circulation as a means to preheat the A and B side components of TerraThane Geotechnical systems prior to use. Pre-heating or recirculation can cause the following issues if left un-checked:
- Though no one raw material may be heat sensitive, however in combination, degradation may occur at high heat for an extended period of time.
- Extended exposure to heat can shorten the shelf life of the B side.
- 140F (60C) is the maximum recommended processing temperature for most of our TerraThane geotechnical polyurethanes.
- Some TerraThane specialty B side systems specifically in the Strata-Fill line up contain an HFO which by itself boils at 89F (31.6C). During the re-circulation process, if allowed to escape to the atmosphere, the HFO loss can increase density and decrease performance of the system resulting in possible project failure.
Re-circulation is typically thought of when the chemical has been allowed to get cold, 50F to 60F (10C to 15.5C) or additional mixing is required. This is not the case with TerraThane systems. Proper planning is the best way to keep the stored chemical up to the recommended temperature for the next day’s projects.
Being Aware of Shipping Schedules to Prevent Weekend Storage:
To maintain the quality and integrity of your shipments, it is important to be mindful of shipping schedules to prevent materials from sitting over a weekend. Shipping carriers often have limited or no operations on weekends, which can result in materials being left in less controlled conditions. This can be particularly problematic for temperature-sensitive products like polyurethane materials. To avoid potential issues, we recommend coordinating with your suppliers and shipping carriers, such as ordering earlier in the week, to ensure that deliveries are scheduled in a way that prevents materials from being left unattended over a weekend. By doing so, you can minimize the risk of exposure to unfavorable environmental conditions and ensure that your materials arrive in the best possible condition for your intended use.
Always consult with NCFI for proper chemical handling and storage recommendations.