A: Nominal dimension is defined as the spacing between two horizontal grids from center to center. Regular nominal dimensions
that Armstrong offers include 600X600mm, 600X1200mm, 2X2” and 2X4”. Actual dimension, the plant standard of product inspection
is defined as the measured size of the product. Actual dimension is smaller than nominal dimension in order to match the grid
system and satisfy the requirements of ceiling installation and maintenance.
Sales volume and total price is evaluated with nominal dimension. The total area of ceilings that customer needs is also measured with nominal dimension.
A: The reasons cause the difference include different system – metric and imperial, different edge detail and different width
of grid face. Therefore, the actual dimensions are adjusted to satisfy the installation requirements.
Normally, the actual dimension of the back of Tegular board is slightly smaller than that of Lay-in board which with the same nominal dimension to reduce the damage of the Tegular edge during the installation.
Since actual dimensions are adjusted to match different grid system, it is tremendously important to choose the right grid system.
A: Armstrong RH70 ceiling is appropriate for relative humidity up to 70%, temperature up to 30°C. Installation shall be carried
out in spaces where the building is enclosed and HVAC systems are functioning and will be in continuous operation.
If the relative humidity is exceeding 70% at your area, Armstrong HumiGuard Plus RH99 is recommended. Armstrong HumiGuard Plus RH99 is formulated to withstand conditions with temperatures up to 49°C and relative humidity up to 99% to inhibit panel sag.
A: Site conditions with excessive humidity, dampness and/or poor ventilation can lead to mold and/or mildew growth on almost
any surface; including concrete. We have no control over such job site conditions, nor can we guarantee that our HumiGuard
Plus RH99 ceiling products will never support mildew.
We recommend that excessive humidity and dampness be treated with a combination of dehumidification, ventilation and air conditioning the space affected.