Pacific Pharmaceuticals manufactures a large range of products, which are stored in the company’s warehouses.
Many of the products are temperature-sensitive and must be stored at temperatures of less than 25°C. In order to satisfy Good Manufacturing Practice (GMP) requirements, the temperatures in the warehouses are continuously monitored in three zones: under the roof, mid-warehouse, and near ground level.
High summer temperatures resulted in the roof heating up, in turn heating up the air space underneath. This resulted in temperatures in the upper levels of the warehouses rising to 40°C in January 1998.
The effect of this on the operation was:
- Temperature-sensitive stock had to be re-allocated to cooler parts of the warehouse. This involved the unnecessary movement of product and updating of warehouse records
- Temperature activated extraction fans were installed in the roof to try and keep temperatures down
- There was a risk of product spoilage if the temperature rose above 25°C.=
- Heat transfer through the warehouse roof meant the air conditioning plant in the manufacturing and office areas contained within and adjacent to the warehouse consumed more electricity in order to keep these areas cool
In late April 1999, Pacific Pharmaceuticals decided to apply a Thermoshield Radiant Heat Barrier Coating to the warehouse, which stores most of the heat-sensitive product. The objective was to reduce the heat transfer through the roof and lower the under-roof temperatures on hot summer days. The warehouse roof area was approximately 1,000m². Thermoshield NZ Ltd was contracted to supply and apply the Thermoshield coating.
Thermoshield is a water-based emulsion of acrylic resins and ceramic beads. The ceramic beads give the product its heat barrier properties so that a 0.5mm coating acts similar to a mirror to the heat of the sun. Additionally, Thermoshield will extend the life of a metal roof by converting rust into iron phosphate and preventing further corrosion.
After water-blasting the roof, the Thermoshield Heat Barrier Coating was applied in two coats with an airless spray gun to give a final coating thickness of 0.5mm.
The benefits of coating the warehouse roof with Thermoshield have been dramatic. The extraction fans which would normally switch on when the under-roof temperature reached 25°C have not operated at all since the application. There has been no need to move stock around the warehouse and disrupt normal operations.
Analysis of temperature records from April 1998 to April 2000 of the coated and uncoated warehouses shows the effect of the Thermoshield coating has been to reduce the peak roof temperature by 10.9°C. Prior to the Thermoshield application (January 1999), monthly peak roof temperatures rose to 37.8°C. ie 8.4°C above the peak control temperature in the adjacent warehouse. After application (January 2000) the monthly peak roof temperature was only 29.6°C. This was 2.5°C below the control temperature in the adjacent warehouse. Monthly average roof temperatures have been reduced by between 0.3°C and 15°C.
The benefits of the Thermoshield coating are greatest from November to February, the hottest time of the year. On the strength of the results from the first warehouse, Pacific Pharmaceuticals contacted Thermoshield to coat a second warehouse of similar size.