By static type
Type B
Stops brush discharge
Low breakdown voltage fabric that prevents propagating brush discharges, the most energetic discharge type.
Product description
Type B is woven polypropylene manufactured so the fabric's breakdown voltage stays below 6 kV, the threshold set by IEC 61340-4-4, the standard that defines the type system. Below it, the fabric cannot hold the charge separation a propagating brush discharge needs, which is the most energetic and dangerous discharge a bulk bag can produce. Some suppliers specify a tighter fabric than the standard requires; ask, and we will confirm the tested figure for your build.
What Type B does not do is dissipate charge. Surface charge still accumulates on the fabric exactly as it would on a Type A. The bag removes one specific and severe failure mechanism; it does not make the bag antistatic, and it offers nothing against flammable vapors or gases.
Uses
- Dry flammable powders with a minimum ignition energy above 3 mJ
- Operations with no flammable vapor or gas in the atmosphere
- Sites wanting protection from propagating brush discharge without a grounding procedure
Industries we supply this for: Chemical, Ingredients, Food Service, Mineral
Do not use
- Environments containing flammable vapors or gases
- Powders with an MIE at or below 3 mJ, specify Type C or Type D
Important
Type B is frequently mistaken for an antistatic bag. It is not. It prevents propagating brush discharge and nothing more; charge still accumulates on the surface.
Configurable options
Everything below is specified per order. Nothing here is a fixed catalogue number.
| Construction | U-panel, four-panel, circular, baffle |
|---|---|
| Top | Open, duffle, flap, spout, conical spout |
| Bottom | Flat, spout, conical spout, full bottom discharge |
| Loops | Corner (four-point), cross corner, tunnel |
| Fabric | Coated or uncoated |
| Liner | None, loose, glued-in, liner choice affects the classification |
| Add-ons | Document pouch, sift-proof seams, custom print |
Customizable options
Every option below is available on this product. They change how the bag fills, lifts and empties.
Lift loops
Corner loops
One loop sewn into each corner seam. The standard build, and the most affordable way to lift a bag.
Cross corner
Sewn into eight points across opposite corners, so the loops stand upright and the forklift operator is not fishing for four floppy straps.
Tunnel loops
A sleeve of body fabric spanning each side, corner to corner. The forks go straight through: the easiest pick where headroom is tight.
Stevedore straps
Double-layer straps across the corner loops, so the bag can be taken on one or two points instead of all four.
Double loops
Two lifting points instead of four, where that suits the load and the lift better.
Top
Spout top
A cylindrical spout sewn into the top panel. 14 in diameter by 18 in long as standard, sized to your filling head.
Spout top with flap
A spout top with a flap panel over it, tied down so the spout stays covered in transit.
Duffle top
A skirt the full width and depth of the bag, so the top opens completely and ties closed.
Flap top
A closed panel with a flap sewn along one seam, tied down over the mouth.
Open top
No panel at all. Fastest to fill where dust and weather are not a concern.
Conical spout top
A top panel that tapers up into the spout. Double spout tops are available too, specified to your filling equipment.
Bottom
Discharge spout
The standard 14 by 18 in spout, tied off. A wider spout is worth specifying for material that bridges.
Flat bottom
Closed base for product that is emptied by tipping or cutting.
Full bottom discharge
The whole base opens, for material that will not flow through a spout.
Spout protection
A flap, or a petal or iris closure, over the discharge, for when the spout must stay clean in transit.
Conical discharge spout
The base narrows into the spout, which helps product that is slow to flow empty completely. Specified to your equipment.
Add-ons
Baffles
Corner panels that hold a cube instead of a bulge: roughly 25 to 30% more volume in the same footprint, and it stacks safely.
Sift-proof seams
Filler cord sewn into the seam, for product fine enough to work through the stitching.
Document pouch
A sealed pouch for the paperwork which needs to travel with the bag.
Safety bands
A reinforcing band around the top, for added strength at the lift.
Custom print
Up to four sides, for branding and traceability on the line.
Liner
No liner
Fabric alone, where the product needs no barrier. The cleanest liner is the one you never have to specify.
Loose liner
Dropped in, not attached. Affordable insurance against fine powder finding the seams.
Glued-in liner
Bonded to the bag so it stays in place through filling and discharge, which is what a food or pharmaceutical audit expects to see.
Antistatic liner
Specify this inside a Type C or Type D bag, so the liner carries the same static classification as the fabric.
Foil liner
Designed for product that is filled hot, the foil laminate holds temperatures that would deform a polyethylene liner.
Fabric
Uncoated
Breathable, and the default build.
Coated
A thin polypropylene coat over the weave, for fine powder and moisture resistance.
Frequently Asked Questions
What is a propagating brush discharge?
A discharge that occurs when charge builds on both faces of a thin insulating layer and then releases in one event. It carries far more energy than an ordinary brush discharge, which is why Type B fabric is engineered to prevent it.
Does a liner change the classification?
It can. An ordinary polyethylene liner inside a Type B bag can reintroduce the insulating layer the fabric is designed to control. Liner and fabric have to be specified together. Tell us if you need one.
My MIE is unknown. What should I order?
Do not default to Type B. An unknown MIE should be treated as low until tested, which points at Type C or Type D. Our build-a-bag flow walks through this.
Related products
Type C
Conductive threads woven into an interconnected grid, terminating in a grounding tab. Must be grounded in use.
Type D
Static-dissipative fabric that bleeds charge safely into the air, with no ground connection required.
Type A
Plain woven polypropylene with no static protection, the baseline bag, and often the right one.
Send us the load, not a part number.
Material, fill weight, how you fill and how you discharge. That is enough for us to come back with a specification.