OBJECTIVETo study the main factors affecting sound-insulation effects of control rooms in workshops with noise, so as to improve the protection.

METHODSThe sound-insulation effects of 467 control rooms were determined, and different building materials, structures of door and window, airtight states etc. were analyzed.

RESULTSThe affecting factors contributed to the sound-insulation effects (Eta(2)) were in the order: airtight states (0.168), building materials (0.080), structures of window and door (0.030, 0.029), sound pressure levels and frequency spectrum's characteristics (0.008, 0.006). Under airtight state, the sound-insulation effects of different building materials of the rooms were as follows: double bricks [(19.6 +/- 3.5) dB(A)]; single brick [(15.4 +/- 3.4) dB(A)]; plank [(13.1 +/- 1.6) dB(A)] or aluminum alloy plate with glass [(13.4 +/- 2.5) dB(A)] (P < 0.01). Of 4 group rooms, with the same structure of doors but double or single bricks of windows. 3 groups with dormant window had higher sound-insulation effects [(15.9 +/- 2.8), (18.7 +/- 3.6), (19.3 +/- 2.5) dB(A)] than those with casement window [(14.1 +/- 2.4), (14.9 +/- 2.3), (16.5 +/- 2.4) dB(A)] (P < 0.01 or P < 0.05); 2 groups with dehydrated window [(18.7 +/- 3.3), (22.6 +/- 3.8) dB(A)] higher than those with dormant window [(15.9 +/- 2.8), (19.9 +/- 3.0) dB(A)] (P < 0.05). Of 6 group rooms, with the same structure of windows but double or single bricks of doors, only in 1 group with double-layer door had higher sound-insulation effect [(18.7 +/- 3.6) dB(A)] than that with single-layer door [(15.9 +/- 2.8) dB(A)] (P < 0.01).

CONCLUSIONThe control room should be designed rationally, kept airtight, according to the sound pressure levels and the condition of the workshop.