By Lizelle van der Berg, director – GCCA South Africa
Insulated panel systems are ideally suited for thermally controlled environments such as cold storage freezers, coolers, food processing and packing facilities.
Equally, insulated panel systems can be applied to atmospheric controlled environments where, in virtually all cases, finished product protection and hygienic control is of utmost importance. We have a wide variety of panels available in South Africa and globally from Polystyrene (EPS), Polyurethane (PUR), Polyisocyanurate (PIR), Phenolic, Rockwool to Mineral Fibre etc., but the question is: “What do you need to consider when choosing insulated panels for your facility?”
Tammy Grove, manager of Kingspan South Africa explains that the factors that determine insulation choice are durability, cost, fire performance, thermal performance and vapor tightness. “Choosing third party insurer approved panels that have low U-values, backed with long term manufacturer warranty on structural and thermal performance would provide peace of mind for the cold store investor for a safe, high performance and long-lasting cold store,” says Grove.
Insurance & fire
Danie van Zyl, divisional manager: corporate practice at Marsh explained that buildings with polystyrene sandwich panels have been featured in several severe high value fire losses over recent years. The fires, which often occur in the food industry, have had a marked effect on how the fire risk posed by polystyrene panels is viewed by insurers.
This is exacerbated by the fact that many firefighters believe that the risk to personal safety posed by a fire in this construction means that internal firefighting should not be attempted. Van Zyl further explains that there has been increased interest in alternative panel materials in recent years.
The fire performance of these varies from those panels which are largely non-combustible (such as mineral fibre) through to combustible panels. Non-combustible sandwich panels utilise core materials such as mineral foams, fibres and aggregates but still contain a small quantity of combustible adhesives. Maintaining panel integrity and preventing premature panel failure is important.
Register for free to gain access the digital library for Cold Link Africa publications
For new construction, van Zyl suggests the following:
- Providing ‘fire breaks’ by replacing sections of combustible panel with non-combustible panel.
- Consider the use of non-combustible or less combustible alternative panel materials.
- Sprinkler Installation and Fire Prevention Planning must be driven by the requirements in the Rational Fire Design (RFD).
The RFD is based on a ASIB or SANS standard and will include sprinklers in the high-risk areas but will help to avoid costly sprinkler installations by compartmentalisation where possible.
If you plan to be in the industry for a long time and your budget is truly limited, Avron Karan from Karan Beef agrees that you should at least build intermediate fire walls in between rooms. Jaco Ollewagen, Technical Manager of CCS Logistics says,“Using a panel that has the proper fire rating is 1st choice but can be expensive. Alternatives can include installing non-combustible panels at strategic locations to serve as fire breaks while using fire rated boards installed behind Electrical DB’s to further reduce the risk and one could also make use of IBR sheets to improve the fire rating around the building.”
Grove points out that stringent insurance industry requirements have led to the development of specific insurer-driven large-scale fire tests, to assess the reaction to fire performance of insulated panels with different cores. “FM Approvals is one of the most renowned insurance and risk management enterprises providing testing and certification services for property loss prevention products and services used in commercial and industrial facilities. FM Approved panels are subjected to a significantly more rigorous test regime and their mark is recognised and respected worldwide,” says Grove.
Another important factor to consider when it comes to fire is the amount of smoke released from panels when they are exposed to fire. You would want the lowest smoke release rating, meaning that if insulation is exposed to flames, the toxicity will not be harmful to your employees, the surrounding community, nor the environment. Grove highly recommends selecting FM Approved insulated panels to minimise damage to your property from any fire risk in the future. In case of fire, the right panel can prevent substantial property damage, as well as ensure that employees are able to escape without the panel walls losing integrity and their exposure to harmful smoke emissions is reduced.
When meeting with Karan, it was evident that risk mitigation was a corner stone to their decision-making process. They took the approach of passive fire protection over the more common active fire protection, often seen throughout the South African landscape. Their rationale was that active fire protection such as a sprinkler system would still lead to a long period of inactivity in the event of a fire. Rather they looked at reducing the likelihood of a fire spreading in the first place, which they believed would leave less down time if a fire were to break out. Thus, more focus was placed on the components utilised to construct the facility.
Their reasoning for a Rational Fire Design was to try to produce a final product which collaborated with their risk mitigation ethos. Each environment is different, each may lend itself more to certain materials than other. One has to do their research prior going to market to find a suitable product and more importantly a suitable supplier of this product with the necessary inhouse skills and the backing to stand behind their offering.
Register for free to gain access the digital library for Cold Link Africa publications
Energy efficiency
Christo van der Merwe, of MRE Marine and Refrigeration Engineering, explains that insulated panels reduce the amount of heat that enters a freezer store through the walls and ceiling, provides a vapour barrier to reduce the moisture that enters the cold space and provides a secure, hygienic enclosure for the containment of product.
These functions are critical to the effective operation of a cold store which is to achieve a desired room temperature while operating with a reasonable power consumption. Heat load from the walls and roof is the heat load that is affected by insulated panels. If the insulated panel wall thickness is increased, then the amount of heat entering the store will be reduced. The power consumption is directly proportional to the amount of heat that enters the cold store and must be removed to maintain the low temperature. If the amount of heat that enters the store is reduced, then the power consumption will reduce accordingly.
MRE considered two different cold store sizes, using 200mm Polystyrene panels, to quantify the effect of increasing the thickness of the panels. It was noted that:
- The heat load from the walls and roof was a similar percentage for small and large cold stores at 25% vs 20%.
- The saving in heat load to increase the panels to 250mm was similar at 7% vs 6%.
- The saving in total heat load is similar as a percentage for the larger store but the more efficient ammonia plant results in a longer payback period.
- The saving in running costs justifies the additional capital expenditure for increasing the insulated panel thickness.
Grove explained that cold store operators should pay attention to the U-Value of the panels to determine their thermal performance and that core types achieving low U-values with the lowest thickness will provide the maximum storage space for cold stores. “With the technological advancements in panel composition, one can obtain a greater thermal result from a thinner offering – thus, a higher R-Value per mm of panelling” says Karan. R-value refers to a material’s ability to resist heat transfer at a certain thickness.
When looking for a material to insulate your building you would generally look for a material with a high R-value, and therefore, one that can resist heat transfer well. U-value assesses the rate of heat loss through a given thickness of a building element (roof, wall, or floor). Ideally you would want a material which gains a small amount of heat in any given time, so you would want the U-value of a material to be low.
Warrantees
Karan explains that product offerings both locally and abroad are improving on a continuous basis. Be it EPS or PIR, more companies are producing better products, and these companies need to find alternate ways of differentiating their offerings on the market. It is in these added services or values that a company may truly differentiate themselves from their competitors in the market. Once you have whittled down your choices and have a good sense of the offering in the market, one needs to look at the ability of these supplier to look after you as a customer long after the deal has been concluded. Comfort can be found in long term warranties as this is a sign of commitment and confidence by the supplier with their offering. The characteristics of the offering should not change in the short to medium term, so why should a warranty not be coupled to the performance of the panelling?
Grove suggests that cold store operators familiarise themselves with the different terms and warranties offered by different manufacturers. One example is that warranties can fall away when certain panels are used in a different application beyond what it was sold for. Ensuring that you are familiar with the terms and warranties offered can prevent further capital expenditure in the future. For the capital investment made, you want your supplier to offer the maximum number of years warranty.
Register for free to gain access the digital library for Cold Link Africa publications