Why do Pharmaceutical Warehouses require a controlled environment?

Pharmaceutical warehouses are critical components of the pharmaceutical supply chain. A warehouse associated with a pharmaceutical manufacturing facility will typically be used for the storage of:

  • raw materials including Active Pharmaceutical Ingredients (API)
  • excipients,
  • intermediate product,
  • finished products,
  • packaging materials and
  • consumables used in the manufacturing process.
  • essentially, a warehouse associated with the pharmaceutical distribution facility will be used for the storage, handling, and distribution of finished products.

Storage Condition Requirements for Pharmaceutical Warehouses

Most of the pharmaceutical raw materials and finished products will have specified storage conditions requirements such as temperature, humidity, and light exposure. The purpose of the storage conditions requirements is to maintain the stability, safety, efficacy, and shelf- life of the pharmaceutical product.

Normally, pharmaceutical raw materials will be stored in airtight containers to prevent exposure to high humidity conditions and in opaque containers to prevent light exposure. In a similar manner, humidity-sensitive pharmaceutical finished products will be packed in humidity barrier type materials such as aluminum foil, glass bottles etc. and may include desiccant material inside the container to absorb moisture. The light sensitive pharmaceutical products will be packed in opaque material such as aluminum foil, opaque PVC/PVDC or in opaque bottles or vials.

Therefore, the most critical condition that needs to be maintained in pharmaceutical warehouse is the temperature. The pharmaceutical warehouse needs to be designed and built in such a way to achieve desired temperature conditions, so as to maintain the stability, safety, efficacy, and shelf- life of the pharmaceutical product.

Design Considerations for Pharmaceutical Warehouses

In terms of the National Construction Code (in Australia), Class 7 buildings are designated generally as “storage-type” buildings, noting that the Class 7 classification has 2 sub-classifications:

  • Class 7a – these are carparks.
  • Class 7b – these are typically warehouses, storage buildings or buildings for the display of goods (or produce) for wholesale.

Of course, a warehouse often forms part of a pharmaceutical facility – as such, the entire building can have “mixed uses” and can therefore also have mixed (or multiple) classifications, where one such (part) classification will be 7b. The design of the facility will generally need to align with the requirements of this classification, as well as the relevant regulations, standards and guidelines.

Given the area and volume of most warehouses and the (product) storage condition requirements for control, heat gain (largely in summer) is a significant consideration for the suitable operation of the warehouse i.e. within the parameters.

Warehouse can gain heat in summer through various mechanisms:

  1. Solar Radiation: The building’s roof and walls absorb sunlight, leading to an increase in internal temperature.
  2. Infiltration: Warm air can enter the warehouse through openings, cracks or poorly sealed doors or windows.
  3. Conduction: Heat can transfer through the building materials, especially if they have low insulation properties.
  4. Equipment and Lighting: The operation of machinery, equipment and lighting inside the warehouse can generate heat.
  5. Occupancy: Human presence contributes to heat through body heat and activities.

Figure 1: Typical warehouse heat gains (of a case study facility)

You will see that such techniques are generally considered to be “passive” – noting that these techniques are not dissimilar to the (5) key principles of Passive House:

  • Make it airtight. …
  • Focus on thermal insulation. …
  • Fresh air through mechanical heat recovery ventilation. …
  • High-quality windows and doors. …
  • Be gone, thermal bridging!

After implanting the above (passive) techniques to reduce the heat gain, a heat load calculation needs to be performed and then an engineering solution may be necessary to achieve the desired temperature conditions.

There are several “active” engineering solutions that can be additionally deployed to achieve desired temperature conditions:

  1. Installation of High-Velocity Low-Speed (HVLS) fans to adequately ventilate the area and promote effective heat dissipation.
  2. Installation of an Air Handling System (AHU) with an Evaporative Cooling System, which uses the natural process of water evaporation to cool the air – this is considered to be an energy-efficient and environmentally friendly method commonly used in cooling applications.
  3. Installation of an Air Handling System (AHU) with a chilled water-cooling system, that utilises chilled water to cool the air.
  4. Installation of an Air Handling System (AHU) with a refrigerant cooling system, that utilises refrigerant to cool the air.

Once an engineering solution is designed, installed, and commissioned, thermal mapping of the area needs to be performed to confirm the temperature conditions in the warehouse. Thermal mapping will involve placing calibrated temperature data loggers at pre-defined ‘worst-case’ locations for one or two consecutive days under empty conditions and 5-7 consecutive days under full conditions during peak summer. The data from thermal mapping will show the highest and lowest temperatures reached during the mapping period, the peak heat time as well as cold and hot spots in the warehouse.

The warehouse temperature needs to be continuously monitored by installing temperature sensors at identified hot spots, and a warning system should be in place to alert users in the event of temperature being exceeded.

Based on thermal mapping data and by way of a collective management approach here, several procedures may also be adopted to minimise the exposure of pharmaceutical raw materials and products to high temperature during summer months, ultimately with the intent to provide guarantee that the temperature (range) is NOT exceeded:

  1. Minimise the stock holding in the warehouse.
  2. Segregate the warehouse based on cold and hot spots.
  3. Use hot spot areas to store non-temperature sensitive materials, such as packaging materials.
  4. Use cold spot areas to store high-temperature sensitive materials such as Active Pharmaceutical Ingredients (API).
  5. Minimise the use of heat generating equipment in the warehouse during peak heat time.
  6. Minimise the opening of large doors to load and unload trucks during peak heat time.

Building a pharmaceutical warehouse or upgrading your existing warehouse – PharmOut can help?

PharmOut can help you with commissioning, qualification, temperature mapping and monitoring. PharmOut can provide the equipment, assist with protocol development, execution, data analysis, reporting, project management and anything in between.

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