Quality & Standards
Built to a standard,
tested to prove it.
ISO 9001:2000Certified by Direct Assessment Services in May 2008Every belt is made against a named standard and backed by test data. Here is the process, the lab, the grade requirements, the fabric and the tolerances behind every figure in our catalogue.
How a Boston belt is made
Six stages, each checked before the next begins.
01
Compounding
Rubber, carbon black and chemicals are weighed and mixed to the grade recipe on the mill.
02
Calendering
The compound is sheeted to exact gauge and the fabric is frictioned with skim rubber.
03
Building
Checked fabric, skims and covers are laid up into the green belt, ply by ply.
04
Press curing
The belt is vulcanised under heat and pressure in the hydraulic press, section by section.
05
Trimming and inspection
Edges are trimmed, width and thickness measured, every roll inspected and tagged.
06
Testing
Specimens from the run are tested in the lab against the grade requirements below.
Every grade claim, tested
The tests behind the numbers in our catalogue and on every datasheet.
Tensile strength of covers
17 / 24 MPa, N17 / M24
Dumbbell specimens pulled to break. N17 demands 17 MPa, M24 demands 24 MPa.
Elongation at break
400 / 450 %, N17 / M24
How far the cover stretches before it breaks. 400% for N17, 450% for M24.
Abrasion loss
≤ 90 mm³, DIN-W
Volume lost against a standard abrasive drum, in mm³. Lower is better.
Ply adhesion
≥ 3.5 N/mm, ply to ply
Force to peel cover from ply and ply from ply. Minimum 3.5 N/mm between plies.
Full thickness breaking strength
100% of rated kN/m, minimum
The belt pulled whole to its rated kN/m and beyond.
Cover hardness
± 5 Shore A of declared
Shore A hardness, held to ±5 of the declared value.
Ageing resistance
70°C oven ageing, held in limits
Oven aged specimens must keep their strength within limits.
Want a test witnessed?
Buyers and third party inspectors are welcome to witness tests on their order.
What each cover grade must achieve
Minimum requirements of the standard for each grade. Our compounds are made to clear them, and the certificate shows by how much.
Tensile strength, minimum
Higher is stronger
Elongation at break, minimum
Higher is tougher
Abrasion loss, maximum
Lower lasts longer
Heat resistance, continuous
Material temperature on the belt
Reinforcement fabric chart
The woven fabric inside the belt decides its strength. Pick a fabric type to see its weave, and every fabric we lay against the belts it builds.
EP · Polyester-Nylon
The world default. Polyester along the belt for low stretch, nylon across for impact and troughing.
4 plies of EP 160 make EP 630/4. Elongation at break is at least 10% on every fabric.
Warp strength per ply
N/mm, with ply gauge, ply weight and the belts each fabric builds
Gauge and weight are nominal per ply. Linked builds open in the catalogue.
Quality management, independently certified
Certified by Direct Assessment Services in May 2008
Bhandari Group (Boston Rubbers) was certified to ISO 9001:2000 for the manufacturing and supply of conveyor belts, transmission rubber belts, V-belts and rubber parts. The same discipline runs the plant today: written procedures, recorded tests and traceable batches.
- Standard
- ISO 9001:2000
- Certified by
- Direct Assessment Services
- Issued
- 21 May 2008
- Scope
- Belts and rubber parts
The standards we build to
Quote any of these in your tender or purchase order. Our quotations state compliance clause by clause.
Indian standards
Conveyor belting, general use
The Indian standard for textile belting. Defines M24 and N17 cover grades, carcass construction, tolerances and tests.
Heat resistant belting
Requirements for HR and SHR heat resistant grades.
Oil resistant belting
Requirements for oil resistant covers.
Fire resistant belting
Fire resistance and antistatic requirements for surface installations.
German standard
Textile belting, German standard
The world reference for cover grades W, X, Y, Z and belt designations. Our export specifications follow it.
International, belting
Textile belting, international
International specification for rubber covered textile belting, grades H, D and L.
Belt widths and lengths
The standard width series: 300, 400, 500, 650, 800, 1000, 1200 mm and up.
Test methods
Flame resistance test
The laboratory flame test behind every fire resistant claim.
Adhesion test
Measures how strongly covers and plies bond to each other.
Abrasion test
Rotating drum abrasion test. The mm³ loss figures in our grade table come from it.
Tolerances we hold, and the certificate you receive
Dimensional tolerances
Test certificate
EP 630/4 5+2 X
| Test | Method | Required | Result | |
|---|---|---|---|---|
| Tensile strength | ISO 37 | ≥ 24 MPa | 26.1 MPa | ✓ Pass |
| Elongation at break | ISO 37 | ≥ 450 % | 488 % | ✓ Pass |
| Abrasion loss | ISO 4649 | ≤ 150 mm³ | 128 mm³ | ✓ Pass |
| Ply adhesion | ISO 252 | ≥ 3.5 N/mm | 4.6 N/mm | ✓ Pass |
| Breaking strength | ISO 283 | ≥ 630 kN/m | 668 kN/m | ✓ Pass |
| Cover hardness | ISO 48 | 60 ± 5 Sh A | 62 Sh A | ✓ Pass |
Specimen layout with illustrative values. Your certificate carries the results of your own production run.
Need a datasheet or certificate for a tender?
Every belt in the catalogue has a printable datasheet. Certificates come with each supply.