Modular Anti Vibration Pad with EVA Foam Core
Acrefine API-MC is a combined EVA and rubber pad of patented modular design (D654,757): a closed-cell EVA foam core bonded between two modular rubber layers, made of 50 × 50 mm blocks. Compared with a solid rubber pad such as API-M, the foam core gives more deflection and a lower natural frequency, so it isolates lower-speed machines. It is used under floor-mounted plant such as heat pumps, air-conditioning condensers, compressors, generators, pumps, fans and other building services equipment.
Construction and Dimensions
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Thickness: 24.00 mm (15/16").
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Construction: two 6.00 mm (1/4") single-sided modular rubber layers bonded to a 12.00 mm (1/2") closed-cell, peroxide cross-linked EVA foam core — density 190 kg/m³ (11.9 lb/ft³), Shore C 50 ± 5.
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Load capacity: 250 kPa (36 psi), i.e. 64 kg (141 lb) per 50 × 50 mm block.
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Deflection at max. load: 5.40 mm (0.21").
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Modules: 50 × 50 mm blocks. They can be cut apart with a sharp utility knife, but a fine-tooth saw gives a cleaner, square edge; for many pads, the pre-cut sizes save time. Pads must be used in full modules.
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Fixing holes: not pre-drilled, but every block has a moulded fixing-hole position. 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. Where the machine is bolted down, cut or drill the hole through the pad on site.
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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 |
64 kg (141 lb) |
| 100 × 100 mm |
4 |
255 kg (562 lb) |
| 150 × 150 mm |
9 |
574 kg (1265 lb) |
| 200 × 200 mm |
16 |
1020 kg (2249 lb) |
| 250 × 250 mm |
25 |
1593 kg (3512 lb) |
| 350 × 350 mm (full sheet) |
49 |
3123 kg (6885 lb) |
Values are per pad at 250 kPa (36 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 6.8 Hz; two stacked pads about 4.8 Hz and three about 3.9 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: if the machine is bolted through the pad, 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.
