Choosing PIR wall panel thickness for the building’s heating pattern

Assess humidity, ventilation and equipment that gives off heat. Storing dry goods creates different conditions from parking wet vehicles. Use the design requirements for the intended activity. “Lightly heated” is too imprecise a specification for ordering panels.

Consider the doors between zones as well. Frequent access to a warmer office affects the heat balance and the movement of moist air. Base the temperature zones on how people actually use the building.

In one example range of through-fixed PIR wall panels with steel facings, the 80, 100 and 120 mm variants have Uc values of 0.27, 0.22 and 0.18 W/(m²K), respectively. These figures illustrate differences within this range. Other PIR products of the same thickness can have different values.

Check the data for the configuration on offer and which corrections its value includes. Joint, facing and application must match the documentation. Dividing core conductivity by thickness alone cannot establish the suitability of the complete wall. Junctions and openings also affect the design.

Take 96 m² of uninterrupted wall and a temperature difference of 30 K. Reducing U from 0.27 to 0.18 W/(m²K) reduces the instantaneous heat flow through that area by 259.2 W. Multiply the change in U by the area and temperature difference. The result applies to those specific conditions.

Annual energy savings depend on temperatures over time, heating hours and use. A weekend workshop has a different heating schedule from an office. Multiplying a winter heat-flow difference by every hour of the year would ignore those differences.

A large door with poorer thermal performance can account for a significant share of façade heat loss. Air exchange when it opens adds to this. Compare door, personnel entrance and window areas with the area of uninterrupted panels. Improving one wall section may not be the most effective first investment.

Check the base, corners and roof junction. Metal components and gaps in the insulation can form thermal bridges. Keep seals continuous too. A locally cold surface in a heated room can encourage condensation. Assess the entire detail as well as core thickness between supports.

If a warehouse will become a workshop or office, describe its future use before ordering. The change may affect insulation, ventilation, fire protection and acoustics. Replacing panels alone may not address every requirement. An early decision lets you adapt openings and the supporting structure as well.

Compare two defined use scenarios and the cost of later alterations before choosing the thickest panel as a precaution. Where future plans are uncertain, record the scenario used for selection and its limits. A future refurbishment can then start with known envelope data.

Check the chosen panel for structural performance, fire requirements and service conditions. Use the load table for the actual span, supports and facings. Colour and sun exposure can influence thermal movement. A suitable U-value does not verify the attachment to the existing frame.

Specify the complete wall variant, lengths, coatings, seals and flashings in the enquiry. Include doors and thermal bridge details in cost comparisons. Select the panel for the zone and for the complete assembly. On that basis you can list the thickness unambiguously in the order.