Solar Radiation Technical Study | Tyvek® Cargo Covers

Estudo de caso

Tyvek® Cargo Covers Solar Radiation Technical Study

Solar Radiation Technical Study

Purpose:
Evaluate the performance of common single use wraps and thermal covers/blankets to determine their ability to protect perishables and temperature sensitive products from temperature excursions during a tarmac delay, when products are subject to solar radiation.

Method:

Test samples – Low thermal mass1 euro sized pallets, each protected with a different cover
Pallet configuration – 18 empty 15” x 15” x 15” boxes stacked 3W x 2D x 3H
Covers tested – Tyvek® low emissivity cover, metallized bubble wrap pre-formed cover, and film based stretch wraps (clear, white & black).
Temperatures measured at top center, south face center, & top southwest corner (hot spots)
Test conducted at weather station in Florida, March 2013.
Full sun exposure with ambient high temperature of 32°C (90°F).
Solar energy measured at 26° north latitude per ASTM G7.
Solar wattage data when clouds obscured sun not shown to remove noise from graph.

Test Load Temperature

Test Data:

Please see image on left

Result:

Solar energy exposure can create temperatures under the cover well in excess of ambient.
Reflective covers performed better (lower peak temperatures) than film based wraps.
Clear stretch film performed worst, with peak temperatures under the cover/wrap reaching 76°C (169°F) → a full 44°C (79°F) above ambient. Clear wraps turn your pallet into a “greenhouse”.
Black stretch film also performed poorly (52°C or 126°F), as it absorbs energy and transmits it via conduction to the palletized load.
White films perform somewhat better at 43°C (109°F) but still transmit significant absorbed energy via conduction to the palletized load resulting in peak temperatures well in excess of ambient temperature.
Metallized bubble wrap pre-formed covers protected loads better than the film based wraps at 37°C (99°F), but do NOT reflect solar radiation as effectively as Tyvek® Cargo Covers, which delivered the best protection at 33°C (91°F), nearly ambient conditions 32°C (90°F).
Tyvek® Cargo Covers (blue trace) reflect and/or block nearly all solar radiation and maintain the load temperature at 1°C above ambient (yellow trace) – the only cover to effectively negate the adverse effects of solar radiation.
Low emissivity Tyvek® Cargo Covers shown. These covers have a proprietary coating which further enhances their ability protect your products against the threat of solar radiation. We recommend low emissivity covers for your most demanding applications.

Benefits Demonstrated:

Tyvek® Cargo Covers provide superior protection from solar radiation, a serious hazard faced during cold chain breaks on the tarmac.
Tyvek® has superior reflectance in the UV and visible spectrum and nearly eliminates the effect of IR radiation through a combination of reflectance, absorbance and low emissivity.
Lightweight thin Tyvek® Cargo Covers can provide better protection against temperature excursion than bulky covers and blankets.

Tyvek® Cargo Covers are the best option to protect against the threats of solar radiation, the leading cause of high temperature excursions on the tarmac.

¹Low thermal mass testing best isolates the relative temperature management effect of the thermal cover or blanket

All technical information set out herein is provided free of charge and is based on technical data which DuPont believes to be reliable. It is intended for use by persons having skill, at their own discretion and risk. The handling precaution information contained herein is given with the understanding that those using it will satisfy themselves that their particular conditions of use present no health or safety hazards. Since conditions of product use are outside of our control we make no warranties express or implied in relation thereto and therefore cannot accept any liability in connection with any use of this information. Nothing herein is to be taken as a license to operate under, or a recommendation to infringe any patents.

To maintain efficacy, DuPont™ Tyvek™ air cargo covers must be stored in the original package under dry, normal temperature conditions. DuPont™ Tyvek™ air cargo covers have been designed for one-time or limited use in line with sanitary regulations and pest management best practices. Sufficient pre-cooling and correct temperature management from start of the cool chain is essential for optimal performance. DuPont is not liable for product damage during the use of the cover.

Technology by blueye® is a registered trademark of Blueye, LLC.