CROHMIQ fabric is a patented, woven polypropylene static protective Type D fabric used in the manufacture of ungrounded bulk bags or FIBC (Flexible Intermediate Bulk Container) for use in flammable gas, vapor and dust atmospheres. FIBC constructed of CROHMIQ fabric provide static protection by dissipating the static charge buildup on the FIBC and by limiting the energy of discharges to prevent an ignition of the flammable environment.
CROHMIQ static protective FIBC are used by Fortune 500 companies and others in a wide range of applications where flammable gas or vapor such as ethylene, toluene or methane or flammable dust such as corn starch, resins, and fertilizers are present.
CROHMIQ FIBC have an outstanding safety record with over 40 million FIBC used since their introduction.
Special patented static dissipative yarns in the fabric dissipate the static charge by corona discharge.
The use of CROHMIQ static protective FIBC eliminates the need for operators to ground the FIBC prior to filling or emptying. The static dissipative performance is provided by the fabric and does not require special FIBC construction methods. The static dissipative property does not deteriorate over the life of the FIBC and maintains its protective properties through multiple refurbishment cycles.
Type C FIBC use a conductive surface or network to conduct the static charge from the surface of the FIBC to a ground. These FIBC provide safe and effective static protection only if they are well constructed and properly grounded. All conductive elements within the Type C FIBC must be interconnected to the grounding tab which in turn must be grounded during filling and emptying of the FIBC.
Type D FIBC do not require grounding to provide safe, effective protection from hazardous static discharges. The fabric has antistatic properties that dissipate the static charges safely to prevent small sparks and potentially explosive discharges. CROHMIQ’s design engineers invented Type D technology, which is protected by multiple patents and patents pending. CENELEC created the Type D FIBC classification after the introduction of the revolutionary CROHMIQ technology.
According to industry experts, a leading cause of industrial accidents involving FIBC is a Type C FIBC with a broken or missing ground connection (see Britton’s article). Isolated Type C FIBC is extremely dangerous because they can produce energetic sparks that can easily ignite flammable gas and vapor and most flammable dust atmospheres. The proper grounding of Type C FIBC is prone to human error. FIBC made of CROHMIQ static protective Type D FIBC fabric have no special construction requirements and do not require grounding.
The potential static hazards at the locations where FIBC are filled and emptied are dependent on the type and form of the product conveyed, the material handling system during filling or emptying, the flammable environment, and the safety procedures in use. Just as FIBC have a 5:1 or 6:1 safe working load, the FIBC should have a level of safety on static protection. An evaluation of the materials used, machinery, and processes is required to determine the static discharge hazard.
CENELEC, the European Committee for Electrotechnical Standardization, was created in 1973 and is a non-profit technical organization composed of the National Electrotechnical Committees of 23 European countries.
The IEC (International Electrotechnical Commission) was founded in 1906 in St. Louis, Missouri, and is presently comprised of 40 countries including the U.S.A. Its stated purpose is to establish standards for a wide variety of electrical products to encourage international trade.
Two tests are required to prove the safety of Type D FIBC: breakdown voltage measurement on fabrics, and ignition testing of full-size bulk bags. The test methods are specified in the International Standard IEC 61340-4-4.
Breakdown voltage determines a fabric’s ability to prevent dangerous propagating brush discharges (PBD). A specimen is placed between two electrodes the voltage increased until electrical breakdown occurs. The fabric is considered safe against PBD if breakdown occurs below 6 kV.
For ignition testing, charging rate (current), Minimum Ignition Energy (MIE) of the flammable material, and relative humidity are the critical test parameters amongst several that need to be controlled in order to establish safe performance of Type D bulk bags.
The test method closely simulates industrial handling of powders using a test apparatus that fills and empties FIBC with polypropylene pellets under controlled environmental conditions. A flammable gas probe is used to measure the ignition hazard of the static discharges from the FIBC using gas mixtures of defined MIE. The test parameters specified in IEC 61340-4-4 are intended to simulate the worst case conditions expected in industry.
CROHMIQ FIBC have been successfully tested using the method described in IEC 61340-4-4 by leading test laboratories, customers, and even competitors under a wide variety of test conditions. TEXENE maintains a state of the art testing facility as part of its ongoing commitment to safety, research, and new product development.
CSC™ stands for Continuous Safety Certification™, which is a unique program provided by Texene to its customers and end-users. The CSC Program involves initial safety qualification of CROHMIQ static protective bulk bags to ensure each design meets the essential safety requirements of IEC 61340-4-4 for Type D FIBC. After initial safety qualification, random samples of production of CROHMIQ bulk bags are re-tested to ensure that they continue to provide the safety required by end-users.
CROHMIQ static protective FIBC have been refurbished with wet and dry cleaning processes and reused by customers. A properly designed program for refurbishment including safety testing may allow multiple reuses of a CROHMIQ FIBC.
When purchasing Type D FIBC for your application, it is important to understand the nature of the static hazard and the level of safety required to protect your employees and customers. The FIBC is just one element of an electrostatically safe and effective material handling system. Look carefully at the test method, the MIE, and the charging rates used, to determine safe performance level.
TEXENE is proud to offer CROHMIQ fabric to a global network of FIBC Suppliers. These leading FIBC manufacturers will design, produce, and deliver FIBC made of CROHMIQ static protective Type D FIBC fabric to your specifications anywhere in the world. CROHMIQ fabric is available in two colors, CROHMIQ blue™ and CROHMIQ white™. Contact our Sales & Service staff for more information or to locate.