Abstract
This work investigated the absorption characteristics of eight types of carpets that are especially designed and manufactured for masjids and two types of carpets pads. Measurements were carried out in the reverberation room according to ISO 354. Each type was tested three times: first when it was installed directly on the floor, second when it was installed above 5.7 mm of polyurethane foam, and last when it was installed above 10 mm of polyethylene foam. The results showed that the absorption coefficient is directly proportional to frequency and knot density. The results also demonstrated that adding pads of polyurethane or polyethylene foam increased the absorption, principally in the mid-frequency range. The effect of polyurethane foam on absorption was higher than that of polyethylene foam. Finally, the absorption coefficients of the examined carpets were found to be close to those of Muslim worshippers when they are in the position known as "standing in rows". (C) 2015 Elsevier Ltd. All rights reserved.