Type C vs. Type D FIBC Bulk Bags: Which Anti-Static Bag Do You Actually Need?
If you handle flammable powders, dusts, or solvents in bulk quantities, anti-static FIBC selection isn't a purchasing decision — it's a safety decision. Get it wrong, and you've created the conditions for an ignition event regardless of which bag you bought.
Type C and Type D FIBCs both provide electrostatic protection. They're both approved for Zone 1 and Zone 2 hazardous areas. They're both used by chemical manufacturers, pharmaceutical processors, food facilities, and plastics operations around the world. But they work completely differently, they fail differently, and the right choice depends on factors specific to your operation — not just your product.
This guide breaks down exactly how each bag works, where each one is the appropriate choice, and the questions you need to answer before you specify either one.
Choosing Between Type C and Type D: The Questions That Matter
1. Can you guarantee verified grounding at every point of use?
This means: every filling station, every discharge location, every operator, every shift — with zero exceptions. If your operation has fixed grounding infrastructure, controlled filling environments, and documented grounding verification as part of a formal procedure that's actively enforced, Type C may be appropriate.
If any of the following apply, Type D deserves serious consideration:
Multiple filling locations or mobile filling equipment
High operator turnover or variable shift staffing
Outdoor or field filling operations
Multiple warehouses or distribution sites with variable infrastructure
Any situation where grounding verification is difficult to audit consistently
2. What does your classified area designation require?
Both Type C (when grounded) and Type D are approved for Zone 1 and Zone 2 classified areas per IEC 61340-4-4. Your EHS team or facility engineer should be involved in the specification decision, particularly if your classified area assessment was performed under ATEX or NEC standards. In some cases, facility-specific requirements may dictate one option over the other.
3. What liner will you use?
This is a frequently overlooked specification decision that can defeat the protection of either bag type. Standard polyethylene liners are non-conductive — they create a barrier between the product and the conductive fabric of a Type C bag, and they prevent the corona discharge process in a Type D bag.
For both Type C and Type D applications requiring a liner, you need a conductive or dissipative liner specifically rated for ESD-protected FIBCs. Our liner team can help you specify the right liner gauge and construction for your application.
4. What is your cost sensitivity across a full program?
Type D bags carry a price premium over Type C, typically in the range of 15–30% depending on configuration. For operations running high-volume programs, that premium adds up. But it should be weighed against the full cost of a grounding compliance program — infrastructure installation, operator training, audit procedures, and the liability exposure of an ungrounded bag in a classified area.
For many operations, particularly those with multiple sites or mobile filling environments, the operational cost of a rigorous Type C grounding program approaches or exceeds the price premium of Type D — before accounting for liability.
When Type C Is the Right Choice
Fixed filling stations with permanent, verified earth ground connections at every point
Controlled single-site operations with consistent, well-trained operators
Formal grounding verification procedure that is actively enforced and audited
Budget-sensitive programs where the price premium of Type D is a meaningful constraint
Applications where liner requirements are met with appropriate static control liners
When Type D Is the Right Choice
Mobile or variable filling locations where consistent grounding cannot be guaranteed
Multi-site operations where grounding infrastructure and procedures vary
High-turnover environments where training consistency is a challenge
Operations where grounding verification is difficult to audit
Any application where the consequence of a missed grounding step is unacceptable
Outdoor or field handling environments without fixed grounding infrastructure
A Note on Genuine Crohmiq Fabric
Not all Type D bags are created equal. Crohmiq is a licensed, proprietary fabric manufactured by Texene to precise specifications. The quasi-conductive thread geometry, placement, and electrical characteristics are engineered to deliver reliable corona discharge across the full range of operating conditions the standard covers.
Generic "Type D" bags exist in the market. Before specifying any Type D bag, confirm the fabric is genuine licensed Crohmiq — and request the test documentation that confirms IEC 61340-4-4 compliance for the specific configuration you're buying.
Capro Industries supplies bags made with authentic Crohmiq fabric. Request technical documentation for any Type D order.
Ready to Specify the Right Anti-Static Bag?
Capro Industries stocks both Type C conductive FIBCs and Type D Crohmiq FIBCs for same-day shipping from our warehouses in Los Angeles, Dallas, and New Hampshire. Our team works directly with EHS managers, process engineers, and procurement teams to confirm the right bag construction, liner specification, and compliance documentation for your application.
Contact us to request samples, technical data sheets, or a quote — or use our FIBC sizing calculator to get started on the right specification for your product.
