Passive Thermal Protection Systems for Global Distribution: Qualification and Operational GuidanceThe Parenteral Drug Association’s (PDA) latest technical report 72 (TR 72), Passive Thermal Protection Systems for Global Distribution: Qualification and Operational Guidance, was released in October and is the first of its kind to outline selection and user guidelines for passive thermal protection systems.

The use of thermal covers for protection of controlled ambient pharmaceutical cargo is becoming common practice in the industry, however, there has been little in the way of common platform guidance across the industry on a global basis.

This leaves confusion within the sector as to the expected thermal performance of thermal cover protection, in what circumstances to use them, and how to build their use into a risk based approach to GDP compliance.

The PDA Technical Report 72 is designed to help potential users consider the risks, assess the suitability in their supply chain and to incorporate covers into their operations.

The report focuses on passive solutions available in the market, rather than active containers which maintain temperature through power sources. Passive protection includes both thermal covers as ‘thermal protection’ and temperature controlled packaging as ‘temperature control’ systems.


Temperature Control vs Thermal Protection

An important distinction is to understand the difference between ‘temperature control’ and ‘thermal protection’.


  • Temperature controlled packaging solutions (e.g. EPS boxes and phase change systems) offer ‘temperature control’ within certain temperature bandwidths for a qualified period of time


  • ‘Thermal Protection’ solutions (such as thermal covers) offer to ‘slow down’ temperature change in order to provide enough time for the cargo shipments to pass safely through temperature risk points in the supply chain.


Although there is a higher risk to ‘thermal protection’ systems, they generally offer attractive cost savings both in direct purchasing costs and shipping related costs.

Historically there has been confusion throughout the industry about the understanding and capabilities of thermal covers and passive temperature controlled packaging in general. Users have developed false performance expectations, which can result in failure to keep product within required temperature limits, resulting in excursions and product losses.

The PDA Technical Report 72 is the first document to provide practical guidance on qualification and handling, enabling readers to select the right level of protection and take a risk based approach to Good Distribution Practice.

The report is also designed to give clarity and understanding within the industry and to provide a common language. Additionally, it will help to align the temperature controlled logistics sector and provide a more considered approach to using passive protection and to serve the ultimate aim of maintaining product integrity and avoid temperature excursions.


What are the main operational and qualification challenges relating to passive systems?

There are several operational and qualification challenges associated with passive systems. More specifically, the performance of thermal covers is determined by a variety of external and internal elements (e.g. type of cargo, packaging, mass, ambient temperatures, direct sunlight etc.). This level of unpredictability makes it challenging to determine whether a thermal cover is going to provide the required protection. Therefore, potential users have three options; rely on the test data provided by their vendor (which should be assessed for credibility); carry out their own internal or external testing qualification process; or use a combination of the two.

A second and critical challenge faced by users is accurate temperature monitoring, it’s often the case that temperature monitors can’t be placed next to the product. As such, monitors have to be placed outside the packaging, recording the air temperature between the thermal cover and packaging, not the product temperature. The variance between the product temperature and air temperature outside the packaging can be considerable and will fluctuate more rapidly.

Ensuring that the inside air temperature is kept within the product temperature limits is more challenging and require higher grades of protection, which are likely to have higher costs.


How does the report answer these challenges?

The content of the report outlines the differences in protection system characteristics and expected performance. As such, it helps to guide expectations and provide knowledge that will allow the reader to make an informed choice on which systems to investigate, what questions to ask potential suppliers and which ones to consider for testing and approval.

The conclusion of the report is a simple one. By proving guidance on qualification and operational use, TR72 helps users maintain quality, safety and efficacy of products in the supply chain. It is a reference document that can be referred to often in a constantly changing environment both regards legislation and threat.

As a core member of the task force responsible for constructing and writing the report, the approach was to form two separate expert groups that each focussed on temperature controlled packaging and thermal covers. Considerable collaborative work from individuals across pharmaceutical, logistics and protective equipment vendor companies resulted in a thorough and technically robust final report that will serve the industry’s key challenge.


The report is available via the PDA website


If you want to discuss in more detail or think a thermal cover approach could be an effective system for your supply chain, please feel free to get in contact.