Two paths, two different materials
Machinery noise reaches the receiver by two routes at once. Airborne sound radiates from the machine into the space and travels to people and to neighbouring buildings. Structure-borne energy passes through the machine feet into the slab, the pipework and the steelwork, and re-radiates as sound from panels and walls some distance away. Different materials address different routes, and getting this wrong is where most industrial noise budgets are lost.
Work in the order the discipline uses: treat the source, then the path, then the receiver. A machine enclosure is a path treatment. It is worth doing when the source cannot be changed and when the enclosure can actually be closed — which brings up the thing that decides the result.
Which grade, and why
For the airborne path, BB830 is the working grade: nominally 5 kg/m² at about 3 mm according to the manufacturer’s datasheet, reference BB830/20/v2. In a plant the advantage is that the mass arrives in about 3 mm, so an existing enclosure or plant room wall can be lined without rebuilding it and without eating into access or maintenance clearance. The material alone is STC 32 at 3 mm according to the manufacturer, a laboratory value.
For thin steel that rings — guards, covers, hoppers, chutes, ductwork and conveyor panels — added mass is not the fix, because the panel itself is the radiator. Bond BlastVib BB460 damping directly to the panel to reduce the ringing first, and only then consider a mass layer over it if the airborne path still needs it. A quick field test: strike the panel. If it rings on, that is a damping problem.
Where the area carries a fire requirement, or sits near hot work, specify BB830FR. It has been tested by an independent third party to AS/NZS 1530.3:1999, SGS report AJFTS26000525R01_EN dated 3 February 2026, returning indices of 0/0/0/7 with none of the six specimens igniting. Where the dominant noise is low-frequency plant — pumps, blowers, compressors — BB830LF is formulated for that range.
| Situation | Material | Price |
|---|---|---|
| Lining a machine enclosure, plant room wall or ceiling | BB830 | 1,122 /m² (1,049) |
| Thin steel that rings — guards, ducts, chutes, conveyor panels | BlastVib BB460 | 8,688 /roll (8,120) |
| Areas with a fire requirement, or adjacent to hot work | BB830FR | 1,288 /m² (1,204) |
| Low-frequency plant — pumps, blowers, compressors | BB830LF | 1,761 /m² (1,646) |
| Sealing joints, enclosure perimeters and penetrations | BA890 sealant | 321 /cartridge (300) |
| Bonding the sheet to steel, concrete or timber | BA990 adhesive | 428 /cartridge (400) |
The sequence that works
- Identify where the sound actually leaves. Walk the machine and listen point by point, or measure. Do not start by ordering material.
- Close and seal everything that can be closed: maintenance doors, cable entries, the gap under the base frame.
- Openings that cannot be closed — cooling and ventilation — need an attenuator that passes air. Never block a cooling aperture with a barrier sheet.
- Damp the panels that ring with BB460 before adding any mass.
- Add mass with BB830, bonded with BA990, sheets overlapped at the joints, then seal every perimeter and every penetration with BA890.
- Only if the target is still not met, move to a double-leaf enclosure with the two leaves structurally separated.
Where this is the wrong answer
- Cooling and ventilation openings that must stay open. These need a purpose-made attenuator, not a barrier. Blocking them overheats the machine and creates a bigger problem than the noise.
- Vibration transmitted through the machine feet into the slab. That is an isolation problem at the mounts and the base. Lining a wall does not touch this path.
- Reverberation on the shop floor that makes speech unintelligible. That is absorption within one space, not transmission between two. Different material entirely.
- A heavy concrete or dense masonry wall already carrying 250 to 400 kg/m². Adding about 5 kg/m² to that is a rounding error; the door, the louvres and the service penetrations are where the money belongs.
- Surfaces above 93 °C, which exceeds the material’s stated heat tolerance according to the manufacturer. Do not bond it to steam pipework or oven skins.
- Very low frequency, below roughly 125 Hz. Mass alone is weak there; cavity depth and structural separation do the work.
Three Thai sites the material was supplied for
IAC Acoustics (Thailand) supplied BlastBlock material for the three sites below. None of them was installed by IAC; all three were installed by others, which is where the result was actually decided. The before and after levels are quoted according to the project documentation held by BlastBlock. IAC did not take the measurements and has not verified them independently.
| Site | What was treated | Before | After |
|---|---|---|---|
| A state power utility site in Samut Prakarn | A vertical opening in the plant building cladding, screened with a hung barrier sheet | 87 dB(A) | 81 dB(A) |
| A petrochemical plant in Rayong | Pipework lagged with 80 kg/m³ mineral wool, a 3 mm BlastBlock layer and an aluminium outer cover | 103 dB(A) | 79 dB(A) |
| An automotive components plant in Rayong | A shredder and its blower, screened with a barrier wall inside the bay | 102 dB(A) | 86 dB(A) |
The pipework case is the most fully documented. Acoustic camera readings on the same set of valves fell from 103.6, 97.4, 95.8 and 95.6 dB(A) to 81.9, 80.2, 79.9 and 79.3 dB(A). The lagging build-up itself is recorded at Rw 31 dB (C -2; Ctr -3), with one-third octave sound reduction rising from 15.7 dB at 50 Hz to 49.6 dB at 5 kHz, according to the project documentation — a calculated value for that construction rather than a site measurement.