Frequently asked questions (FAQ)

Containment & safety

What is OEB classification?

OEB (Occupational Exposure Band) is a classification that groups the permissible airborne exposure to active substances, expressed as an OEL (Occupational Exposure Limit) in µg/m³. The bands range from OEB 1 (low risk, > 1,000 µg/m³) to OEB 5 (< 1 µg/m³) for highly potent compounds such as HPAPIs and cytotoxics. For engineers, the OEB class determines the required hardware: the higher the band, the stricter the requirements for closed transfer and validation. For purchasers, this drives the Total Cost of Ownership. We advise always establishing the OEB class before selecting the system, in line with high-containment guidelines and SMEPAC validation.

What is a SMEPAC measurement?

SMEPAC (Standardized Measurement of Equipment Particulate Airborne Concentration) is the internationally recognised ISPE method for objectively measuring the containment performance of equipment. The measurement determines how many particles are released during an operation such as coupling, filling or emptying, expressed in µg/m³. This demonstrates whether a system meets the required OEB class rather than only claiming it on paper. A SMEPAC-validated system is essential during EMA and FDA inspections. HECHT performs SMEPAC tests using API surrogates in its Test & Trial Centre.

How does a containment isolator work?

A containment isolator is an enclosed housing under negative pressure in which operators process powders through glove ports without direct product contact. The negative pressure and HEPA filtration keep particles inside the isolator, preventing exposure down to OEB 5 level. The pressure differential (typically −30 to −60 Pa) is the critical parameter that must be continuously monitored. For highly potent substances, an isolator is often the only route that meets GMP and occupational safety requirements.

Handling & processes

What is a big bag (FIBC)?

A big bag, also known as a FIBC (Flexible Intermediate Bulk Container), is a flexible bulk packaging for transporting and storing powders and granulates, typically holding 500 to 2,000 kg. Filling and emptying big bags is a critical moment in the process chain, as this is where most dust emission and cross-contamination occur. The choice between an open or containment design determines the level of operator protection. HECHT supplies filling and emptying systems up to OEB 5 for dust-free, GMP-compliant handling.

What is an endless liner?

An endless liner is a continuous plastic film tube used to transfer powder in a closed manner without the operator contacting the product. After filling, the liner is crimped, sealed and cut, keeping the product fully contained. It is a reliable solution that avoids mechanical complexity and performs up to OEB 5. The liner is a recurring consumable, so usage and supply security factor into the TCO. In the pharmaceutical industry, this technology is standard for transferring highly potent substances.

What is a sampling device?

A sampling device takes a representative sample of a powder or granulate during the process without exposing the product or operator. Variants include screw, slide and vacuum sampling, each suited to a different product flow and containment requirement. Representativeness is crucial: the sample must reflect the actual composition of the batch. A closed sampling system prevents product loss and contamination risk and meets GMP requirements.

What are the applications of a pallet lifter?

A pallet lifter is a lifting and handling aid that safely raises and positions pallets, containers or IBCs within a production process. Its main use is the ergonomic and safe movement of heavy loads, reducing manual handling and the associated injury risk. The combination of lifting capacity, positioning accuracy and any ATEX design is decisive. A lifter reduces operators' physical strain and therefore absenteeism and occupational safety costs.

How does a roll lifter work?

A roll lifter raises and tilts cylindrical loads such as rolls, drums or barrels and positions them in a controlled manner. The system combines a lifting mechanism with a rotation function so the load is emptied safely without manual lifting or tilting. The grip across various diameters and the maximum torque are the critical design parameters. This means less physical strain, lower absenteeism costs and higher throughput in repetitive handling.

How do you choose the right PE bag for powder processing?

The choice of a PE bag (polyethylene) depends on the product chemistry, the required containment class and compatibility with the filling or emptying system. Key parameters are the film thickness, antistatic or conductive properties (ATEX zones) and suitability for sealing and cutting during closed transfer. The material choice determines chemical resistance and the risk of static discharge with flammable powders. In the chemical industry, we always recommend an antistatic version where there is an explosion risk under the ATEX directive.

Industry-specific & certification

What containment requirements apply to API production in the pharmaceutical industry?

In the production of active pharmaceutical ingredients (APIs), the containment requirement is determined by the OEB class of the substance, defined in a toxicologically substantiated OEL. Highly potent APIs and cytotoxics generally fall under OEB 4 or 5, requiring closed transfer, SMEPAC validation and GMP documentation (URS, DQ, IQ, OQ) in line with GMP Annex 1. Each coupling, filling and emptying point must be assessed individually for leakage risk. A supplier with a complete validation package and local service is essential to limit inspection risk.

Maintenance & optimisation

How do you extend the lifespan of containment components?

The lifespan of containment components is mainly determined by correct cleaning, timely replacement of wear parts and avoiding aggressive chemical load outside the specification. Seals, valves and flexible connections are the critical wear parts that must be inspected at fixed intervals. Preventive maintenance lowers the Total Cost of Ownership by avoiding unplanned downtime and rush replacements. In the pharmaceutical industry, we link maintenance intervals to the number of batches so that validation and GMP documentation stay current.

How often should filter and containment components be replaced?

The replacement frequency depends on the process load, the nature of the powder and the pressure drop across the system, and is not determined by a fixed calendar date. The increase in pressure differential is the most important indicator: if it rises above the design value, replacement or cleaning is needed. It is important to keep consumable parts in stock to limit downtime. With abrasive or hygroscopic powders, intervals are shorter than with free-flowing, dry products.

How is containment equipment cleaned in a GMP-compliant way?

GMP-compliant cleaning requires a validated cleaning protocol that demonstrably prevents cross-contamination between batches, recorded in a Cleaning Validation. The choice between Clean-in-Place (CIP) and Wash-in-Place determines the construction: smooth surfaces, minimal dead spaces and stainless steel 316L are essential. Cleanability affects the changeover time between products and therefore production capacity. In pharma and food, we apply design guidelines that measurably reduce residues below the permitted limit.

Transport & dosing

What is the difference between pneumatic and mechanical powder transport?

Pneumatic transport moves powder via an airflow through closed pipelines, whereas mechanical transport uses screws, conveyor belts or elevators. Pneumatic transport offers a fully closed, dust-free system that is flexible to route, but requires attention to particle damage and wear with abrasive products. Pneumatic systems often have fewer moving parts on the floor, simplifying maintenance. In the pharmaceutical industry, engineers often choose vacuum transport for its inherent containment.

How accurately can you dose powders in a closed system?

Dosing accuracy in a closed system depends on the dosing technique, the powder properties and the weighing control, and with gravimetric dosing can achieve a deviation of less than one percent. Dosing screws, dosing valves and loss-in-weight weighing systems are the common solutions, each with its own accuracy range. Higher accuracy means less product loss and a more consistent end quality. In pharma and food, reproducible dosing is crucial for recipe fidelity.

Industry-specific

What requirements apply to powder handling in the food industry?

In the food industry, hygiene requirements apply under HACCP and EHEDG, where equipment must be cleanable, residue-free and resistant to frequent cleaning. This calls for hygienic design with smooth stainless steel surfaces, minimal gaps and food-grade seals that prevent substance migration. A hygienically designed system lowers the risk of recalls and extends lifespan under aggressive cleaning. We apply designs that prevent allergen cross-contamination and support HACCP validation.

What role does containment play in the battery industry?

In the battery industry, containment is essential because materials such as lithium compounds and electrolyte powders are both reactive and health-critical and require a dry, inert environment. This means closed handling under controlled humidity (dew point), often combined with ATEX measures against dust explosion. Process reliability is crucial, as moisture uptake directly affects product quality and cell performance. We supply systems that process powders dust-free and under protective gas, tailored to electrode production.

Why is material selection important in chemical powder handling?

In the chemical industry, material selection determines whether equipment resists corrosion, abrasion and chemical attack from the processed product. The choice between stainless steel 304, 316L, Hastelloy or polymer coatings depends on the pH, temperature and solvent the powder contacts. The right material choice prevents premature wear and costly unplanned replacement. We always recommend a material compatibility check based on the complete substance profile before configuring a system.

Cosmetics industry

What requirements apply to powder handling in the cosmetics industry?

In the cosmetics industry, powder handling centres on product protection, dosing accuracy and preventing cross-contamination between fragrances and colourants. Fine, often poorly flowing powders such as pigments and talc require closed, low-dust handling. Consistent dosing protects product quality and therefore brand reputation. For the cosmetics and pharmaceutical sectors, we apply hygienically designed systems that minimise product loss and contamination.

How do you process fine powders and pigments dust-free?

Fine powders and pigments are processed dust-free through closed transfer via vacuum transport, endless liners or containment filling heads, so no particles enter the working environment. Their low bulk density and high fineness require an antistatic design and careful air management. Dust-free processing means less product loss, a cleaner workplace and lower cleaning costs. We combine closed transport with filtration to safely control even the finest fractions.

Single-use technology

What is single-use technology in powder processing?

Single-use technology uses disposable components such as liners, bags and flexible connections that are replaced after one batch rather than cleaned. This eliminates the cleaning and cross-contamination risk, as each batch starts with a clean, validated part. The cost structure shifts from fixed cleaning and validation costs to variable consumable costs, which is often more advantageous on multi-product lines. In the pharmaceutical industry, single-use is widely applied for highly potent substances and frequent product changeovers.

When do you choose single-use instead of a cleanable system?

The choice of single-use is advantageous with frequent product changeovers, highly potent substances or when Cleaning Validation is complex and costly. Single-use drastically shortens changeover time and removes the risk of residues from a previous batch. The trade-off is a comparison between recurring consumable costs and the saved cleaning, water and downtime costs. On high-volume single-product lines a cleanable system is often cheaper; for multi-product or HPAPIs, single-use usually wins.

What benefits does single-use offer for containment?

For containment, single-use offers the advantage that the product remains fully enclosed in a disposable barrier during transfer, without operators contacting residual product. An endless liner or single-use filling head achieves high containment levels without complex mechanical seals. This reduces the validation burden and inspection risk during GMP audits. We combine single-use barriers with our containment systems to work safely and reproducibly up to OEB 5.

How do you prevent cross-contamination when processing multiple products?

Cross-contamination in multi-product processing is prevented through closed transfer, validated cleaning or the use of single-use components between batches. The deciding factor is whether the system is fully cleanable or whether disposable barriers guarantee a clean start per batch. A well-considered approach lowers the risk of recalls and rejects and speeds up product changeover. In pharma, food and cosmetics, we recommend tailoring the strategy to the number of product changeovers and the toxicity of the substances.

Filtration

What is the difference between bag filters and cartridge filters?

Bag filters and cartridge filters differ in filter area, cleanability and suitable application in industrial dust collection. For engineers, cartridge filters offer a larger filter area in a compact housing and suit fine dust, while bag filters perform better with high dust concentrations and coarser particles. For purchasers, the choice determines the service life of the filter medium, the pressure drop and therefore the fan's energy costs. We advise matching the filter choice to particle size, dust load and the required residual emission under standard.

Which filter media are used in powder processing?

In powder processing, filter media are selected based on particle size, chemical compatibility, temperature and whether the process is dry or moist. For engineers, polyester, PTFE-coated media and PTFE membranes are common, with a membrane layer retaining the finest fractions and improving cleanability. For purchasers, the media choice determines lifespan, replacement frequency and the Total Cost of Ownership. In the pharmaceutical industry, FDA- or GMP-compliant media are used to prevent product contamination.

How do you extend the lifespan of filter media?

The lifespan of filter media is extended through the right cleaning strategy, a correctly set pressure drop and avoiding moisture breakthrough that clogs the medium. For engineers, timely jet-pulse cleaning based on pressure drop is more effective than cleaning at a fixed time interval. For purchasers, a longer service life lowers both material costs and downtime for replacement. In practice, a well-tuned filter installation significantly extends service life and reduces energy costs.

What filtration grade is needed for the pharmaceutical industry?

The required filtration grade in the pharmaceutical industry depends on the application and ranges from fine dust filtration to HEPA filtration (H13/H14) for cleanroom environments. For engineers, the classification under ISO 16890 or EN 1822 determines which medium and seal are needed to achieve the desired separation efficiency. For purchasers, a higher filtration grade affects investment and maintenance costs but is often mandatory for product protection and GMP compliance. We match the filtration grade to product criticality and the applicable cleanroom class.

How do you prevent cross-contamination via the filter system?

Cross-contamination via the filter system is prevented through closed filter changes, bag-in/bag-out (BIBO) systems and validated cleaning between products. For engineers, a BIBO design is essential for highly potent substances, as the contaminated filter is removed without exposing the operator. For purchasers, this lowers the occupational safety and contamination risk and simplifies GMP validation. In the pharmaceutical and chemical industries, we apply BIBO filtration where containment up to OEB 5 is required.