HSE OCE8 Mixing of Drilling Muds (Sack Room)

Controlling Exposure to Drilling Mud Chemicals During Mixing Operations

LEVCentral Expert Commentary

The preparation of drilling muds is a routine but potentially hazardous operation within offshore drilling. During mixing, operators may handle large quantities of powdered additives including barite, bentonite, polymers, weighting agents, corrosion inhibitors and specialist drilling chemicals. Emptying sacks and transferring powders into mixing hoppers can generate significant concentrations of airborne dust capable of causing respiratory and skin exposure if not adequately controlled.

HSE OCE8 – Mixing of Drilling Muds (Sack Room) forms part of HSE’s Offshore COSHH Essentials (OCE) series and provides practical guidance on controlling exposure during these activities. The document concentrates on the engineering controls and working practices required within the drilling mud mixing area, commonly referred to as the sack room.

For LEV professionals, OCE8 is particularly relevant because it demonstrates the application of Local Exhaust Ventilation (LEV) to a dusty material-handling process. Powder transfer points represent well-defined sources of dust release, making them ideal candidates for enclosure and source-capture extraction. The guidance therefore provides another practical example of applying LEV at the point where contaminants are generated rather than attempting to control dust after it has dispersed throughout the workplace.

View HSE Guide

View Original HSE Guidance

Key Learning Points

The guidance covers:

Hazards associated with powdered drilling mud additives.
Dust generation during sack handling and mixing.
COSHH assessment for drilling mud preparation.
Enclosed mixing systems where practicable.
Application of Local Exhaust Ventilation (LEV).
Good general ventilation.
Safe handling of chemical bags.
Preventing spills and dust accumulation.
Good housekeeping and cleaning methods.
Inspection and maintenance of extraction equipment.
Appropriate use of Personal Protective Equipment (PPE).
Respiratory Protective Equipment (RPE) where residual risks remain.
Information, instruction and training for operators.

Source Document Information

Organisation: Health and Safety Executive (HSE)

Document: OCE8 – Mixing of Drilling Muds (Sack Room)

Series: Offshore COSHH Essentials (OCE)

Document Type: COSHH Essentials Guidance Sheet

Primary Topics: Drilling Muds, Powder Handling, Local Exhaust Ventilation, Sack Rooms, Offshore Drilling, COSHH

Audience: Offshore Drilling Contractors, Mud Engineers, Occupational Hygienists, LEV Designers, Health & Safety Professionals, Process Engineers and Duty Holders.

LEVCentral Perspective

OCE8 provides an excellent illustration of one of the most common industrial applications of Local Exhaust Ventilation: manual powder handling.

Although written specifically for offshore drilling operations, the engineering principles apply equally to many industries where powders are transferred from sacks into mixers, hoppers or process vessels. Similar operations are found in food manufacturing, pharmaceuticals, chemical production, plastics, ceramics, construction materials and animal feed manufacture.

The guidance demonstrates that the most effective engineering solution is not simply to install an extraction fan. Instead, dust control should begin with thoughtful process design:

minimise dust release;
contain the transfer point wherever possible;
position extraction close to the point of release;
maintain good housekeeping; and
ensure operators follow suitable working practices.

For LEV engineers, the sack room provides a classic example of source capture. Because the dust release occurs at a predictable location, well-designed extraction can intercept contaminants before they disperse into the operator’s breathing zone.

Further Resources

Recommended Learning

Thought Leadership

Although OCE8 addresses a highly specialised offshore process, it illustrates a universal lesson in occupational hygiene.

Whenever powders are manually transferred from one container to another, there is potential for airborne dust generation. Whether the material is bentonite in an offshore sack room, flour in a bakery, cement in a construction products factory or pharmaceutical ingredients in a blending plant, the engineering principles remain remarkably similar.

The document therefore has value far beyond the offshore sector. It reinforces that effective dust control is achieved by combining good process design, containment, Local Exhaust Ventilation, housekeeping and competent working practices.

From a LEVCentral perspective, OCE8 is another excellent example of HSE promoting engineering solutions integrated into the process itself, rather than relying on respiratory protection as the primary means of controlling exposure.