freight & cargo protection against the cold using thermal pallet covers by tp3 global

Author: Peter Lockett © 2012 TP3 Global Ltd

In association with:

Freight & Cargo Protection Against the Cold Using Thermal Pallet Covers

For Temperature Sensitive Goods Version: 12.12.12

P a g e | 2 © 2012 TP3 Global Ltd

TP3 Global Ltd. Malvern House, New Road, Solihull, West Midlands, B91 3DL, United Kingdom

Tel +44 (0)845 519 1374 [email protected] www.tp3global.com

Introduction

It’s turning cold in Northern Europe countries so protection of controlled ambient cargo and freight

at minimal cost is becoming a challenge.

Many are turning to thermal / insulated covers and blankets (also known as quilts and shrouds) to protect skid and air cargo pallets. The cost of these covers can be very cheap and provide the right level of protection required.

Will Insulated Thermal Covers & Blankets Work?

Unlike traditional TCP (Temperature Controlled Packaging – using EPS and cold packs), thermal

covers and blankets will NOT stop the passage of temperature, they just SLOW IT DOWN (see diagram below) allowing the cargo more time to move through the risk points (temperature spikes).

The main reason thermal covers are used is restricted budget. Typical cost for a Euro skid sized cover is around £25/$40 whereas temperature controlled packaging can be between £150-‐£250 / $240-‐

$400.

If the majority of the supply chain journey is within safe limits of temperature it can be frustrating to have to pay for temperature control packaging (TCP) that is only really required for a couple of short durations points, normally during loading / unloading the transport or aircraft.

For these short periods, thermal covers are ideal as they can delay temperature change long enough

to keep the freight within specified limits.

The main concern with using thermal covers and insulated blankets is the lack of temperature control during the supply chain. This has to be a risk assessment decision based on budget available, the temperature profile of the route and the temperature limits the product is to be kept between.

Managers would normally select the best protection within the budget available. Where possible, this would be TCP, but if this is out of budget, the thermal cover is the next option.

One of the keys to deciding if covers and blankets are suitable is a good understanding of the shipper’s requirements regards temperature limits. Sometimes the shipper needs guidance regards




the difference between storage temperature limits (often tighter) and the distribution temperature

limits as these can differ.

The shipper often wants the lowest cost of logistics but may not understand the consequences and risks involved in shipping under general cargo conditions. If there is a requirement for temperature control, there is a cost to that service in that it requires priority treatment.

A clear understanding of stability data is also required. All too often there is a requirement to keep

produce between 15-‐25C (which can be expensive) but in reality the product may be allowed between 2-‐40C (for example), which can be much easier and cheaper to manage.

Understanding Thermal Performance & Threats

Performance of thermal covers can rely on a number of variables. The two main components are:

1. The nature of the palletised goods (what’s under the cover) 2. The nature of the ambient weather/temperature during the supply chain (what’s outside the

cover)

Under the cover, the physical mass of the product is a key factor. For example, a bulk liquid in large containers will change temperature at a much slower rate than small capsules of liquid.

Packaging can also have a big impact. Cardboard can provide a reasonable layer of insulation so product in boxes will change temperature at a slower rate than the same product wrapped in shrink-‐

wrap.

Outside of the pallet, the temperature differential and the type of thermal threat will impact performance. The larger the difference in (convection) temperature between the product and the ambient, the quicker the internal temperature will change. Passage of ambient (air) temperature

into the palletised goods can be shielded with insulation layers of packaging, covers or blankets. Key to effective protection is secure design of edge sealing and use of correct insulation materials.

The radiation threat from direct sunlight is often one of the main causes of temperature excursion when cargo is left on the airport tarmac for too long. The high strength of infra-‐red (IR) light (which

makes up nearly half of the spectrum) has a high impact on surface heat so resistance against IR is an important aspect of any protective product.

In a similar way, visual light also accounts for nearly half of the spectrum (ultra-‐violet is around 7%) and although is less harsh than IR, does impact temperature and should be defended against with

effective materials.

Selecting & Testing Thermal Pallet & Air Cargo Covers

Many companies test covers with their own palletised produce to see what performance they achieve. Others consider the performance data provide by the manufacture to give some indication. Some simply select the cheapest in order to ‘tick the box’.




At present, there are no official standards for testing of thermal covers, although it’s something that

the Parenteral Drug Association (PDA) is looking at. This can make it almost impossible to compare thermal pallet covers without carrying out internal tests. A reasonable manufacture should be able to supply at least some basis test data to provide some reassurance of performance. It’s common to

see both controlled chamber testing (hot and cold) as well as direct sunlight trials.

The type of produce used on the pallet and its configuration are key to providing useful data. The British Standard for testing thermal bag systems for food containers (BS EN 12546-‐2:2000) indicates use of 50% thermal mass. For this reason, many manufactures use bottled water due to neutrality,

availability and cost. This enables base test data with the view that further testing can be carried out with customer relevant goods later.

Understanding the positioning of temperature monitors is critical. The outer edges of the pallet load, particularly the corners, will always give away temperature first (like getting cold fingertips) whilst

the central core of the pallet will hold temperature the longest. It’s therefore important to see the temperature recorder readings at the corner edges of the pallet rather than the core.

Whether to Use a Thermal Base

Enclosing the palletised goods completely with a thermal base will improve the thermal performance. Local testing has shown around a 10-‐15% improvement but this could vary depending

on load type etc.

A fully encompassed load with top and base if sealed properly can also help as a contamination, pest and insect barrier.

Some companies have automated palletising systems that don’t allow the flexibility to fit a thermal base during

the process. In this situation, there are two options:

1. Use the double pallet system where the finished pallet is placed onto a second pallet fitted with a thermal base

2. Use a second thermal cover top, this could improve the performance by around 40-‐60% and negate the requirement for a base

If you are unable to use a base and the thermal cover top is airtight (i.e. with no rips, gaps or holes), it is normally quite effective in preventing ambient air entering through the open base. This is helped by that fact that the product itself prevents much of the risk of entry. If the cover is ripped, the

internal air can escape and make it easy for the ambient air to enter under the cover from the open base.




Single Trip Cover or Reusable Blanket?

Thermal pallet blankets and quilts are normally made from more expensive materials to help with

durability. This helps to maintain integrity when the units are being reused constantly. Blankets are perfect in a closed loop operation or where they are being used locally without the risk of being lost.

Thermal pallet covers are normally made from effective but lightweight material with the focus on balancing performance with cost. These are normally used where there it’s not practical or too

expensive to return the units to origin.

Many companies use bubble wrap insulation with reflective foil outer facing to reflect sunlight. These can usually be purchased as a roll, or made to fit specific pallet sizes.

Buying a roll of insulation gives the flexibility to protect any size and configuration of air cargo or skid pallet, although it can take considerable time to wrap each unit (20-‐40 minutes). Also, as with any

manual operation, there is the risk of leaving gaps etc. that may affect thermal integrity.

If working with similar configured pallets on a regular basis, it’s often advisable to purchase ready-‐made covers to size. These tend to be fitted very quickly (2-‐5 minutes) and can add a level of reassurance and consistency regards thermal performance (good for QA Managers).

An Alternative to Silver Backed Bubble Wrap

One of the negative aspects of silver backed bubble wrap is the volume it takes up during shipping

and storage (it’s normally between 5-‐40mm thick depending on performance required). For this reason, there is gravitation within the industry to look at alternative high tech materials that have similar performance but are much thinner.

Technology is evolving quickly in the materials market and a number of companies (like TP3) are now

offering effective solutions that are made of materials that are only 1mm or less in thickness. These materials tend to be easy to work with, fold up into tiny packages (comparatively) and are thermally effective.

Summary

Single use thermal pallet covers are ideal where budget is too restrictive for the more expensive TCP

but where some form of protection is required.

Useful Resources

Please see our Resources page (http://www.tp3global.com/resources.html) for the following:

• FAQ on Use of Thermal Covers in Pharmaceutical Logistics • Videos of cover fitting etc.




TP3 Global Product Range

Silverskin™ PP100

Silverskin™ PH300

SilverBubble™ PB500

Image

Suitability Superlight, low cost material for light pharmaceuticals & general perishables

More robust and heavier material Ideal for ambient pharmaceuticals & higher value perishables

Thicker, insulating silver backed bubble wrap for additional protection – ideal for LTL (truck based logistics)

Durability Single use / trip Single trip but fairly robust so reuse a possibility

Single use / trip unless return logistics feasible

Thickness ~0.7mm ~1.0mm ~7.0mm

Weight (g/m2) 115g/m2 172g/m2 150g/m2

Material Type Reinforced nitrocellulose multi-‐layer coated foil laminate

Multi layer laminate with reflective metal foil outer skin

Nitrocellulose coated aluminum foil (both sides) double layer bubble wrap

Waterproof Yes Yes Yes

Reflectivity Over 95% 97% (ASTM E 408) Over 95%

U Value n/a (single skin) n/a (single skin) 0.170m2K/W

Please request thermal performance data from [email protected]

freight & cargo protection against the cold using thermal pallet covers by tp3 global

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