Back to Basics, Equipment and Machinery Safety

Back to Basics: Machine Guarding Requirements

Back to Basics is a weekly feature that highlights important but possibly overlooked information that any EHS professional should know. This week, we examine OSHA’s standards for machine guarding in the general, construction, maritime, and agricultural industries.

Working with machinery and moving machine parts is common in many workplaces, and according to OSHA, it has the potential to cause serious injuries amongst employees such as crushed fingers or hands, amputations, burns, or blindness. Safeguards are necessary for protecting workers from these kinds of injuries, and any machine part, function, or process that may cause injury must be safeguarded. If injuries occur from machine operation or accidental contact, OSHA says the hazards must be eliminated or controlled.

OSHA’s machine guarding standards outline the guidelines that employers should use when implementing procedures and safeguards in their workplaces. Machine guarding hazards are covered in the standards for general industry, construction, maritime, and agriculture.

General requirements

Employers are required by OSHA to provide one or more methods of machine guarding to protect the operator and other employees from hazards such as those created by point of operation, ingoing nip points, rotating parts, flying chips, and sparks.

The point of operation is the area on a machine where work is actually performed upon the material being processed. The point of operation must be guarded by a device that complies with any appropriate standards or is designed to prevent the operator from having any body part in the danger zone during the operating cycle. Special hand tools for placing and removing material should be used as supplementary protection to allow easy handling of materials without risk of hand injury.

Some of the common machines that require point of operation guarding are:

  • Guillotine cutters
  • Shears
  • Alligator shears
  • Power presses
  • Milling machines
  • Power saws
  • Jointers
  • Portable power tools
  • Forming rolls and calendars

According to OSHA, revolving drums, barrels, and containers must be guarded by an enclosure that interlocks with the drive mechanism so that the barrel, drum, or container cannot revolve unless the guard enclosure is in place. When fan blades are exposed less than 7 feet above the floor or working level, the blades must be guarded with guards that have openings no larger than a half inch. Lastly, machines designed for a fixed location have to be anchored to prevent walking or moving.


In the construction industry, OSHA requires that all hand and power tools and similar equipment shall be maintained in a safe condition and equipped with guards during use when designed to accommodate them. The following must be guarded if exposed to contact by employees along with any reciprocating, rotating, or moving parts:

  • Belts
  • Gears
  • Shafts
  • Pulleys
  • Sprockets
  • Spindles
  • Drums
  • Fly wheels
  • Chains

OSHA states that guarding must meet the requirements in the American National Standards Institute, B15.1-1953 (R1958), Safety Code for Mechanical Power-Transmission Apparatus.

Employers must make sure that the employees using hand and power tools have personal protective equipment to protect them from falling, flying, abrasive, and splashing objects, and from harmful dusts, fumes, mists, vapors, or gases to which they may be exposed.


According to OSHA, in the maritime industry, “guarded” means shielded, fenced, or enclosed by covers, casings, shields, troughs, spillways, or railings, or guarded by position or location. The danger zones on machines and equipment used by employees must be guarded. Fixed machinery must be secured to prevent shifting or movement, and machines driven by belts and shafting must have a belt-locking or equivalent protective device if the belt can be shifted.

Machinery should have an effective exhaust system at the point of origin when chips and dust produced by the machine may be hazardous to the user. OSHA requires that a power cutoff device be provided at the operator’s working position, and during any machine repair, adjustment, or servicing, the power supply must be turned off, locked out, and tagged out.

All machinery must be maintained in a safe working condition, and only designated employees should do the maintenance or repairs on that machinery or equipment. Also, machines with defects that affect the safety of operation must not be used. OSHA provides specific guidance for hand-fed circular ripsaws, hand-fed circular crosscut table saws, swing cutoff saws, radial saws, band saws and band resaws, abrasive wheels and machinery, and rotating parts, drives, and connections in the maritime machine guarding standard.


The machine guarding standard for the agriculture industry applies to all farm field equipment, farmstead equipment, and cotton gins, OSHA states. Employers must ensure that all guards are kept in place when machines are in operation, and not allow riders on farm field equipment other than the people required for instruction or assistance in machine operation.

Employers must install and use guards, shields, or guarding by location, and if those options are not feasible, they should install a guardrail or fence. Guards must be designed and located to protect against inadvertent contact with the hazard being guarded, OSHA says, and each guard and its supports must be capable of withstanding the force of a 250-pound individual if they lean or fall onto the guard. Guards must also be free from burrs, sharp edges, and sharp corners, and they must be securely fastened to the equipment, machinery, or building.

Guarding by location is when no employee can inadvertently come in contact with the hazard during maintenance, servicing, or operation because of the location. Employers should use guardrails or fences that are capable of protecting against employees inadvertently entering the hazardous area. OSHA provides additional requirements on guards for farm field equipment like tractors, farmstead equipment, and cotton ginning equipment in the agriculture standard.

For more details and the full OSHA machine guarding standards, click here.

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