Belting Impact Resistance

Careful consideration of loading conditions must be considered in conveyor belt selection. If there is a history of belt failure, this may be more significant than any guides, tables or calculations.

Improvements in load design and/or conveyor equipment may be required if belting is prematurely failing from material impact. Indications of an impact problem include:

Breaks in belt parallel to belt angle
Star breaks to top cover
Gouges in top cover
Failure of mechanical lacing from physical abuse

To calculate number of plies required, first determine the lump weight factor (Table E₁), including calculated variables, and then determine minimum plies to withstand impact from Tables E₂ or E₃.

Table E₁ -- Lump Weight Factor in Pounds

Density

Lump Size -- Inches

lbs ft3	2	3	4	5	6	7	8	9	10	12	14	16	18
50	0.4	1.3	3.0	5.8	10	14	21	30	40	70	100	148	211
75	0.6	1.9	4.5	8.6	15	21	31	44	61	105	149	222	316
100	0.7	2.6	5.9	12	20	28	41	59	81	140	199	296	421

125	0.9	3.2	7.4	14	25	35	52	74	101	175	248	371	527
150	1.1	3.8	9	17	30	42	62	89	121	210	298	444	632
175	1.3	4.5	10.4	20.2	35	49	73	104	142	245	348	518	737

Density may be determined from Table E₄. Table E₁ may be used to determine lump weight factor that must be adjusted as follows:

If free fall is different than 4 feet, divide Lump Weight Factor by 4 and multiply by free fall of material in feet.
If material momentum includes a chute preceeding free fall, add to the above the value determined by multiplying the distance of drop in chute area times the size of the chute angle squared.
[Additional factor = h (sine Angle in degrees)²]
If large lumps exceed 10% of material, add one more ply to minimum table rating (E₂).
If impact idlers are not used, multiply the lump factor by 2 for belts 4-ply and less, by 1.25 for 5-ply belts, and 1.15 for 6-ply and over belts.

For multiple-ply belts, use calculated lump factor to determine minimum number of plies to resist impact from Table E₂. For reduced-ply belts, use Table E₃.

Table E₂Maximum Impact Rating Multiple-Ply Belts

MP Fabric Identification

Number of Plies	35	43	50	60 & 70	90 240
3	8	16	20	38	48
4	16	28	38	62	80
5	40	60	75	175	320
6	120	160	210	475	700
7	240	320	410	775	1060
8	-	520	660	1050	1440

Table E₃Maximum Impact Rating Reduced-Ply Belts

Number of Plies	75	105	125	150
2	10	20	45	110
3	60	105	200	290
4	150	280	430	600
5	300	500	800	1000


	lbs per ft³


	Alumina Ammonium Nitrate Asbestos Ore Asbestos, Shred Ashes, Dry Ashes, Wet Asphaltum Batch Glass Bauxite, Run of Mine Borax Brickwork (solid) Bagasse Caliche Carbon Black, Powder Carbon Black, Pellets Cement, Portland Cement, Clinker Cinders Clay, Dry in Lump, Loose Coal, Anthracite, Egg Coal, Anthracite, Nut and Stove Coal, Anthracite, Run of Mine Coal, Anthracite, Pea Coal, Anthracite, Buckwheat Coal, Bituminous, Sized Coal, Bituminous, Run of Mine Coal, Bituminous, Slack, Dry Coal, Bituminous, Slack, Wet Coke, Sized Coke, Mixed Coke, breeze Coke, Petroleum Concrete Cinder w/Portland Cement Sand & Gravel, Portland Cement Mix Wet Copper Ore Copperas Cryolite Cullet Dolomite, Crushed Earth, Common Loam, Moist Earth, Mud, Fluid Feldspar, 1/8" Flue Dust, Blast Furnace Fluorspar Glass Batch Gneiss Grains Barley (48 lb/bu) Corn, Shelled (56 lb/bu) Flour, Wheat (190 lb/bbl) Oats (32/lbbu) Rye (56 lb/bu) Wheat (60 lb/bu) Granite Gravel, Dry, Screened Gravel, Run of Bank Greenstone, Broken Gypsum, Irregular Lumps Hemetite, Ore (Nelsonite) Illmenite, Concentrate Iron, Ore Iron, Ore, Crushed Lignite, Air-Dried Lime, Ground Lime, Pebble Limestone, Broken Limestone, Coarse, Sized Limestone, Dust Marble Metals Aluminum Brass, Cast Copper, Cast Cast Iron Wrought Iron Steel Lead Zinc Mill Scale Molybdenum Ore Nickel Ore Paper Pulp (Wet) Phosphate, Rock Phosphate, Pebble Potash Ore, 6" Potash Ore, 14 Mesh Quartz, Broken Salt, Rock, Crushed, 3/8" Salt, Granulated Sand, Dry Sand, Damp Sand, Foundry Sandstone, Quarried and Piled Shale, Crushed Sinter Slag, Furnace, Crushed Slag, Granulated Slate, Crushed, �" Soybeans Sugar, Raw Sugar, Refined Sulphur, Ore Sulphur, Lumpy Sulphur, Powdered Taconite Pellets Titanium Dioxide, Dry, Fine Traprock, Crushed Wood and Wood Products Hardwood (solid) Softwood (solid) Woodchips, Hard Woodchips, Soft Woodchips, Cooked Bark Bog Fuel, 40% Moisture Woodflour Sawdust Zinc Ore, Crushed

50-65
45
80
20-25
35-40
45-50
80-85
90-100
80-90
45-55
115
7-10
100
4-6
25
94
80-95
40-45
60-70
60
60
60
60
60
50
50
40-45
55
25-30
23-32
25-34
35-40
115
115
150
115-125
120-150
50
62
80-120
90-100
73
110
65-70
110-125
80
90-100
96

38
45
35-45
26
44
48
90-100
90-100
90-100
107
70-80
140-160
150-155
120-200
150
45-50
60
50-55
90-100
95-100
75-85
95-105

165
512
542
446
485
490
710
438
125-150
100
100
60-62
75-85
85
75-85
68-75
95-100
80
70-80
90-110
110-130
90
82
90
110-135
80
60-65
80-90
46
55-65
50-55
87
75-85
50-55
115-130
50-55
105-110

35-75
25-40
18-30
16-25
35
10-20
16-22
16-36
13
160

	Angle Repose
22� 40� 50� 31� 39� 30� 35� 35� 27� 27� 27� 30� 35� 35� 40� 40� 45� 30� 45� 40� 35� 38� 23� 21� 21� 23� 28� 38� 38� 30� 35� 35� 43� 30� 35� 35� 30� 25� 25� 36� 25� 25� 45� 39� 39� 25� 25� 28� 35� 22� 22� 45� 36� 38�


	Table E4 Weights of Material (Density)