What Is a Nip Point
A nip point is any location where two rotating parts, rotating and stationary parts, or parts moving toward each other converge and create a hazard capable of catching and crushing fingers, hands, clothing, or hair. Common examples include the contact point between a rotating shaft and a fixed surface, the mesh of two rotating gears, or the rollers in an industrial mixer.
OSHA does not use the term "nip point" in a single unified regulation, but the hazard falls under the general duty clause (Section 5(a)(1) of the OSH Act) and machine-specific standards in 29 CFR 1910 subpart O. Employers must either eliminate the nip point hazard or provide effective guards and safeguards to prevent worker contact.
Where Nip Points Occur
Nip points appear in industrial and commercial settings far more than most people realize. Manufacturing facilities with conveyor systems, printing presses, industrial mixers, compressors, and laundry equipment all present nip point hazards. In homes, nip points can exist in power drills, bench grinders, ceiling fans with exposed motor components, and some older washing machines without protective covers.
The severity of injury from nip point contact depends on the equipment's rotational speed and force. A slow-moving mixer may cause bruising, while a high-speed industrial press can amputate fingers or hands. Entrapment in a nip point typically happens within seconds, leaving little time for escape.
Prevention and Control
OSHA's hierarchy for nip point hazards follows the standard control approach:
- Elimination: Redesign equipment to eliminate the rotating component or change the process entirely
- Engineering controls: Install fixed guards, barrier guards, or interlocked devices that stop rotation when accessed
- Administrative controls: Implement lockout/tagout (LOTO) procedures during maintenance, establish restricted access zones, and require operator training on specific equipment
- Personal protective equipment: Require tight-fitting clothing (no loose sleeves or jewelry) and hair restraints where nip point hazards cannot be fully eliminated
Guards must be inspected regularly as part of your facility's safety audit schedule. A functional nip point guard should prevent hand access to the hazard zone using the probe test described in ANSI B11.19 standards for machine safety.
Home and Small Business Context
Homeowners rarely think about nip points until an accident occurs. Power tools like bench grinders and handheld drills create nip point hazards when sleeves catch on rotating bits or wheels. Before using any rotating equipment at home, inspect the guard integrity and ensure it has not been modified or removed for convenience.
Common Questions
- How do I test if a guard adequately protects against nip point hazards? Use a 6-mm smooth probe or your finger to try to access the rotating component. If the probe reaches the hazard zone, the guard is inadequate and must be replaced or modified.
- What should happen during emergency procedures if someone's clothing becomes caught in a nip point? All rotating equipment should have an emergency stop button within arm's reach of the operator. Establish clear protocols to shut down the equipment immediately, never attempt to manually extract caught material, and call emergency services if entrapment involves skin contact or injury.
- Are older machines exempt from nip point guard requirements? No. OSHA standards apply to all machinery regardless of manufacture date. Retrofitting guards on legacy equipment may be required during a safety audit or inspection.