Modular Anti Vibration Rubber Pad for Plant and Machinery
Acrefine API-M is a double-sided modular rubber pad made of 50 × 50 mm blocks. Its blocks separate along grooves, so a pad can be sized on site in whole modules; each block has a fixing hole, and the 10 mm profile keeps the machine low. It reduces structure-borne vibration and noise from floor-mounted equipment such as pumps, compressors, air-conditioning condensers, heat pumps, generators, fans, workshop machinery, and gym and sports equipment. It is also used under the base plates of pipe supports.
Construction and Dimensions
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Thickness: 10.00 mm (3/8").
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Load capacity: 65 kg (143 lb) per block, i.e. 255 kPa (37 psi).
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Modules: 50 × 50 mm blocks joined by thin grooves. Cut them apart along the grooves with a utility knife. Pads must be used in full modules.
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Fixing hole: not pre-drilled. Every block has a moulded 9 mm hole position, supplied closed: open it for an M8 bolt, or for larger bolts up to M16, cut the thin rubber web to enlarge it to Ø18 mm. The block corners are quarter circles, so where four blocks meet, for example at the centre of a 100 × 100 mm pad, there is another hole position.
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Full sheet: 357 × 357 mm (14" × 14"), 7 × 7 = 49 blocks.
Load Table
| Pad size |
Blocks |
Max. load per pad |
| 50 × 50 mm |
1 |
65 kg (143 lb) |
| 100 × 100 mm |
4 |
260 kg (573 lb) |
| 150 × 150 mm |
9 |
585 kg (1290 lb) |
| 200 × 200 mm |
16 |
1040 kg (2293 lb) |
| 250 × 250 mm |
25 |
1625 kg (3583 lb) |
| 350 × 350 mm (full sheet) |
49 |
3185 kg (7022 lb) |
Values are per pad at 255 kPa (37 psi), with the load evenly spread over the pad. The 50 × 50 mm and 100 × 100 mm sizes are sold in packs of 4. Load–deflection properties independently tested by Materials Engineering & Testing Ltd (UK), 2016.
How to Choose and Install
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How many pads: divide the weight of the machine by the load per pad and round up. Place the pads under the feet or base frame so each one carries a similar share of the load.
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Natural frequency: at full load a single pad gives about 11.1 Hz; two stacked pads about 7.9 Hz and three about 6.4 Hz (estimated from static deflection, per industry practice). A lower natural frequency isolates lower-speed machines.
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Stacking: separate each layer with a steel plate so the load spreads evenly across the pad below.
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Bolting down: use an elastic washer or grommet under the bolt head, so the bolt does not bridge the pad and carry vibration into the floor.
About Acrefine
Acrefine Engineering designs vibration isolation and seismic restraint products for building services and industry. Fixing Smith is Acrefine's official online supplier and ships from UK stock.
