Active vs Passive FIBC Earthing for Type C Bags
A practical comparison of passive FIBC Type C earthing and active monitoring, including resistance verification, standards alignment and safer hazardous area bulk handling.
Active FIBC earthing uses monitored two-point continuity and resistance checks to confirm that a Type C FIBC remains connected to verified earth during filling or emptying. Passive FIBC earthing uses a clamp and cable, but relies on visual checks and does not confirm resistance.
In this article, “earthing” and “grounding” refer to the same electrostatic control principle: connecting the Type C FIBC to a verified earth or ground point so static charge can dissipate safely.
Is active or passive FIBC earthing better?
The short answer is that a monitored electrostatic earthing connection does everything a passive connection does, but better, meeting the requirements of the standards and making for easier, safer bulk material processing operations. For a longer answer, read on…
Clamp and cable only
Passive grounding connects a Type C FIBC to earth using a clamp and cable. It can establish a direct path to earth, but provides no active confirmation that the connection is effective, continuous or within the required resistance threshold.
Monitored connection
Active grounding continuously verifies the connection to earth before and during operation. It monitors resistance, provides a clear GO/NO-GO status and can alert operators or interlock with equipment if grounding is lost.
Why Type C FIBCs need electrostatic earthing
When carrying out processing operations such as filling and emptying Type C FIBCs with flammable bulk materials, electrostatic charge can be generated and, if not controlled, can become an ignition source that leads to a risk of fire or dust explosion.
The best way to prevent this accumulation of electrostatic charge is to set up an electrostatic earthing connection before and during process operations. This can be done with a simple passive earthing solution or a more comprehensive active earthing solution.
For Type C FIBC operations, the important question is not simply whether a clamp is attached. It is whether the bag is confirmed as connected to earth before and during transfer.
Key article insight- Charge can be generated during normal operations as bulk materials move through process equipment and against the FIBC surface.
- Static discharge may be invisible until it becomes hazardous, particularly where flammable gases, vapours or combustible dust atmospheres are present.
- The earthing path needs to remain reliable throughout filling and emptying, not just at the start of the task.
What is passive FIBC earthing?
The main benefit of a passive earthing solution is that it is simple. A direct connection can be made from a Type C FIBC to a local site earthing point via a clamp and cable.
The passive connection uses a single point of contact and must be visually checked by the operator to ensure that it remains in place throughout operations. If a high-quality clamp and cable are used, a reliable connection between this point and the site earth can be established, but the connection would only be between these two points, and the operator would have no confirmation of whether the entire bag is safely earthed, or how high the resistance is between the bag and the earthing point.
What is active FIBC earthing?
An active electrostatic earthing solution takes the benefits of a passive solution and improves on them. By using two points of contact at the top and bottom of the Type C FIBC, an active solution can monitor across the material of the bag and form a closed loop back to the site earthing point.
This helps to mitigate the risk of the contact point or another part of the bag becoming isolated from earth. The active monitoring loop also allows visual indication to be given to the operator when the system detects that safe conditions are met and gives a permissive signal.
With the use of a permissive signal, an active electrostatic earthing solution can use output contacts to interlock with process equipment. This allows additional safety features such as audible and visual indicators when a good connection is made, or automatic shutoff if a connection is disrupted.
Even better, the use of an active electrostatic monitoring system allows sites to meet and demonstrate that they are meeting the requirements of the relevant safety standards and industry best practice.
GO/NO-GO indication
Operators receive a clear visual signal before proceeding with transfer operations.
Resistance verification
The system monitors to the maximum resistance threshold used for Type C FIBC earthing.
Process interlocks
Output contacts can be integrated with process equipment where the site design allows.
How active monitoring supports ATEX, IEC and NFPA expectations
The requirements for electrostatic earthing for Type C FIBCs are set out in national and international standards and industry best practice.
ATEX workplace safety directive
The ATEX workplace safety directive sets out an obligation to avoid the ignition of explosive atmospheres where they occur during industrial hazardous area operations. This includes controlling and mitigating the risks of any possible ignition sources during FIBC transfer operations, including the buildup of electrostatic charge which can cause a spark discharge if not controlled.
This requirement can be met by a passive electrostatic earthing solution assuming that a good connection is established and maintained and can be confirmed to be met with the use of an active earthing solution.
IEC TS 60079-32-1 Technical Specification
The IEC technical specification IEC TS 60079-32-1: Explosive atmospheres - Part 32-1: Electrostatic hazards, guidance gives specific guidance that Type C FIBCs are to be connected to earth during filling and emptying operations.
Again, this requirement can be met with a passive solution assuming that nothing complicates or disrupts the connection and can be confirmed to be met with an active solution which continuously monitors the connection to the site earthing point during operations.
IEC 61340-4-4 and NFPA 77 Standards
The standard IEC 61340-4-4: Standard test methods for specific applications - Electrostatic classification of flexible intermediate bulk containers (FIBC) – which has been adopted globally, forming the basis of national standards including the German DIN EN IEC 61340-4-4 and British BS EN IEC 61340-4-4 – along with the US recommended practice NFPA 77 are aligned in their further guidance that an electrostatic earthing connection of this kind “shall have a resistance to groundable point of less than 1.0 x 108 Ω”
This requirement for a monitored connection with a maximum resistance value to the site earthing point is the key distinction between a passive and an active electrostatic earthing solution.
A passive electrostatic earthing solution must rely on an assumption that a visually inspected connection to earth is good enough, with no confirmation of the resistance. Meanwhile, an active electrostatic earthing solution which continuously monitors to a maximum resistance threshold of 1.0 x 108 Ω gives ongoing confirmation that the requirements of the standards and best practice are being met, and can give both a clear visual indication to operators of the system’s permissive state, and interlock with process equipment to allow automation of additional safety features, further increasing process safety and reliability.
For more context, see Newson Gale’s static electricity safety standards and guidelines and the Type C FIBC application guidance.
What are the benefits of active monitoring?
In addition to improving process safety and conformance to standards and industry best practice, there are a number of other benefits provided by active electrostatic earthing solutions.
FIBC Bag Condition
As with any other reusable item, over the course of reuse Type C FIBCs are subject to wear and tear. While there is as yet insufficient data for a meaningful answer to whether the direction of entropy can be reversed in general, one way that the risk posed by FIBCs in deteriorating condition can be mitigated is to use an active earthing system.
With the use of a continuous earth monitoring loop passing through two points of contact and across the fabric of the bag, an active earthing system can flag to operators if this loop is disrupted due to a break in continuity. Under such conditions, a FIBC might outwardly still look serviceable, but in fact have sections which due to wear and tear have broken down and become isolated from the rest of the bag, which could allow for electrostatic charge to build up if transfer operations were to continue.
Therefore, by not going permissive on a bag suffering from wear and tear of this kind, an active earthing solution would catch a safety issue which would not be visible to the naked eye or to a passive earthing solution, allowing for the problem to be fixed before operators or facilities were put at risk.
Alignment with SOP and Training
Another benefit of an active earthing solution is to align with and support site standard operating procedures (SOP) and training.
It is important to distinguish here that aligning and supporting does not mean that an active earthing solution can or should replace robust SOPs or training for operators. There is no substitute for effective SOPs and trained and competent operators for carrying out safe and reliable hazardous area operations.
Instead, the use of an active earthing solution can help to support the trained and competent operators in the carrying out of their duties in a safe and consistent manner. This can include integrating the operation of the earthing system in a process check list (attach clamp – confirm green light – proceed with transfer operation), save time and site electrician callouts by having clear confirmation of safe earthing conditions, and help to support with internal and external audits for process safety (are we following IEC 61340-4-4? Is the earthing system being used? Yes to both).
In short, using an active electrostatic earthing solution allows trained and competent operators on well-run sites to carry out their responsibilities with increased safety and efficiency.
Active vs passive FIBC earthing: key differences
| Criteria | Active electrostatic earthing | Passive electrostatic earthing |
|---|---|---|
| Connection method | Two-point monitored connection across the Type C FIBC and back to the site earth point. | Single clamp-and-cable connection between the FIBC and a local earthing point. |
| Verification | Continuously monitors safe earthing conditions and resistance threshold. | Visual check only that the clamp is attached. |
| Operator feedback | Clear GO/NO-GO indication before and during the process. | No active status signal; the operator must rely on inspection. |
| Standards support | Conformance to ATEX workplace safety directive, IEC TS 60079-32-1, IEC 61340-4-4, and NFPA 77. | Assumed conformance to some standards, no confirmation of conformance to IEC 61340-4-4 and NFPA 77. |
| Process interlocks | Can interlock with equipment for increased safety and process automation. | Operator control of all equipment. |
| Bag condition insight | Early detection of problems with bag condition. | No indication of condition of bags. |
| SOP and training support | Support for SOPs and operator training. | Limited support for SOPs and operator training. |
Need monitored Type C FIBC earthing?
Newson Gale’s Earth-Rite® FIBC is designed to actively monitor the resistance through Type C bags and provide clear GO/NO-GO indication for operators.
A safer answer to a simple question
Electrostatic earthing of Type C FIBCs is required for safe hazardous area bulk material transfer operations. While a simple passive earthing solution is better than nothing at all, there are some significant limitations to such a solution which can either leave operations open to unmitigated risks, or require significant further investment of time, effort, and money, to make up for gaps in the process.
Conversely, an active electrostatic earthing solution which monitors to the maximum resistance threshold of 1.0 x 108 Ω provides a more comprehensive, safer solution which conforms to the requirements of the relevant standards and industry best practice, and supports trained and competent operators in carrying out safer, more efficient, and more reliable hazardous area transfer operations.
FAQ: passive vs active earthing for Type C FIBCs
Passive vs active earthing systems: which is better?
Should visual indicators or interlock systems be used for static earthing?
How to document IEC 61340-4-4 or NFPA 77 compliance for audits?
How do you calibrate a Newson Gale earthing system for FIBCs?
How should operators be trained on static earthing procedures?
Want to learn more about earthing a Type C FIBC?
Correct earthing is one of the most important controls for reducing electrostatic ignition risk during Type C FIBC filling and discharge. Explore the resources below for practical guidance, demonstrations, and product information.