Modular Sound Enclosures and Acoustic Rooms

Two ways to use a modular sound enclosure

A sound enclosure either keeps noise in or keeps it out. Around a compressor, blower, press or test stand, the enclosure contains the noise at its source. Around people, a quiet room gives operators, supervisors or testers a place to talk, focus and take calls next to a loud process.

Both are built from insulated modular panels with sealed joints, sound-rated doors and windows, and ventilation designed so the air path does not become a noise path.

Workplace noise limits come from OSHA’s occupational noise standard (OSHA noise), which favors engineering controls such as enclosures. This page is part of our in-plant and industrial modular buildings range. For quiet offices on the plant floor see modular in-plant offices, and for equipment housings without an acoustic focus see modular equipment enclosures.

What makes an enclosure quiet

Noise reduction depends on the whole assembly, not the panel alone. The weakest element, often a door, a window or a vent, sets the result.

Rate the wall, then check the room

Panels are compared by Sound Transmission Class (STC), a lab rating for airborne sound through a wall assembly. The noise you hear after installation also depends on the machine’s frequency content, openings and the room around it, so start from measured sound levels at the source and the level you need at the operator position.

Panel options are covered in wall panels and insulation.

Welding and arc-booth sound enclosures

Welding, grinding and plasma cutting are some of the loudest jobs in a fab shop, and they also throw arc light, spatter and fume. A welding sound booth handles all of it in one modular room: galvanized steel wall panels with a non-combustible mineral-wool core, a perforated galvanized inner liner that absorbs arc and grinding noise instead of reflecting it back at the welder, and a roof that keeps noise from escaping over the top.

Each booth is laid out around the process: one or more welding stations, a cutout or offset for a fume extraction arm, a ventilation plenum to move fume and heat out, and doors sized for people, parts carts or a forklift.

What a welding sound booth spec usually covers

• Wall panels: galvanized steel flat panels, commonly 18 gauge, with mineral-wool (rock wool) insulation, a non-combustible core suited to hot work.
• Interior liner: galvanized perforated sheet over the insulation for sound absorption that stands up to spatter and bumps.
• Roof: single-slope or flat roof panels close the top, with lighting and sprinkler coordination planned with your facility.
• Ventilation: an internal plenum or ducted exhaust sized to the welding process, routed so the air path does not leak noise.
• Fume extraction: wall cutouts or offset mounts so an extraction arm reaches the bench without opening a gap in the wall.
• Doors: personnel doors with hardware and interlock or light switches, plus larger doors where parts move in and out.
• Anchoring: mounting plates, floor anchor hardware and internal bracing.
• Shipping: booths can ship in pre-built sections, often two halves, with doors shipped loose, which cuts on-site assembly.

For open welding cells that only need arc screening rather than noise control, welding curtain rolls are the lighter option. For hot-work rooms that need fire-rated walls, see our fire-rated in-plant offices.

Noise control for automotive service departments

Dealership service departments, fleet garages and tire shops are loud in short, sharp bursts: impact wrenches and air ratchets, tire changers and bead seaters, compressors cycling, lifts and the occasional engine at high idle. A study of tire-changing shops at Colorado State University found intermittent peaks above 140 dB, with air ratchets, the bead seater and the tire-changing machine contributing most. Technicians wear hearing protection; the problem is everyone else.

The complaints usually come from the service advisors’ offices, the parts counter and the customer lounge, where noise from the shop comes through doors, thin walls and especially windows. Fixing it takes three different tools, and mixing them up is why many attempts fail.

Put the compressor in its own room

A rotary screw or piston compressor runs all day and is often the loudest steady source in the building. A modular sound enclosure around it, with lined walls, a sealed steel door and silenced louvers sized for the compressor’s cooling air, takes it out of the shop and makes service easier. Size the ventilation from the compressor maker’s heat rejection figure, not guesswork, or the unit will overheat.

The same approach works for a parts washer, a dyno or a tire balancing station that bothers the people nearby. See the machine enclosure design section above for ventilation and access details.

Quiet offices and lounges next to the shop

• Build the office as its own box. A modular room with sound-rated wall panels and its own ceiling, rather than a partition up to a drop ceiling that leaves the plenum open to the shop.
• Treat the windows as the weak point. A wall is only as quiet as its glass and door. Use laminated or insulated sealed glazing, and seal the frames into the panels.
• Seal the door. Solid-core or insulated steel doors with perimeter seals and a drop seal or threshold; an undercut door lets the shop straight in.
• Seal penetrations. Every hole for ducts, cable and air lines needs acoustic sealant.
• Add absorption on the shop side. Panels and baffles in the shop lower the level that reaches the wall in the first place, which helps every room around it.
• Know the rule. OSHA’s noise standard sets 90 dBA as the 8-hour limit and 85 dBA as the action level for a hearing conservation program, and expects engineering controls where feasible (29 CFR 1910.95). Measure before and after so you know what changed.

Many dealers combine the two: absorption in the shop and a modular, sound-rated advisor office or compressor room built in a few days without closing bays. We supply the rooms and enclosures as part of our modular buildings range; tell us what is loud, where people sit and what you have tried.

How a sound enclosure project runs

Send sound level readings, equipment dimensions and photos if you have them. Lead times are covered in modular building lead times.

Related projects

In-plant rooms next to loud, hot processes, where the wall, door, glass and HVAC were chosen as one assembly.

Packsize: offices in a packaging plantIn-plant offices in a corrugated packaging plant: acoustics, paper dust and material flow.

Hydro Extrusions: high-heat metal plantIn-plant offices in a high-heat aluminum extrusion plant: heat load, HVAC and protection.

Frequently asked questions