ANSI B11.0-2023 THTD Compliance: Why Food & Beverage Plants Still Face Machine Injuries

In food and beverage production, where high-speed fillers, slicers, and mixers hum around the clock, ANSI B11.0-2023 compliance on two-hand trip devices (THTDs) is table stakes. Defined in section 3.15.13 as an actuating control demanding simultaneous both-hands operation to trigger hazardous functions—then releasable—these safeguards are engineered for operator protection. Yet, I've walked plant floors from Sacramento to San Diego where THTD-equipped machines meet the standard, but injuries persist. The key? That informative note: THTDs only reduce risk for the operator.

The Operator-Only Protection Gap

THTDs shine at keeping fingers out of danger zones during cycle initiation. Press both palms within 0.5 seconds, 24 inches apart, and the machine fires up—releasing hands starts the motion. But compliance stops there. Non-operators—cleaners hosing down conveyors post-shift, maintenance techs swapping blades, or even a forklift driver edging too close—face unguarded hazards.

Consider a bottling line: THTD-compliant activation prevents operator crush injuries. But during sanitation, when guards are swung open for CIP (clean-in-place) access, a worker's sleeve catches a moving auger. Or a new hire, rushing to clear a jam, bypasses the THTD entirely. OSHA 1910.147 and ANSI B11.19 highlight this: machine guarding must address all foreseeable interactions, not just programmed cycles.

Food & Beverage Specific Pitfalls

Wet, slippery floors amplify risks in plants processing sauces or beverages. THTD compliance assumes dry, stable footing—rare here. I've consulted sites where compliant THTDs on dough mixers didn't stop a slip-induced fall into a running shear.

• Cleaning phases: Machines often run partially for rinses; THTDs don't govern these.
• Setup/changeovers: Guards removed, THTDs irrelevant—exposing pinch points.
• Multi-operator zones: Packers or inspectors reach across lines, beyond THTD reach.
• High turnover: Temps bypass controls instinctively; training lags compliance.

Per BLS data, food manufacturing saw 4,700 nonfatal injuries in 2022, many from machinery despite guarding standards. ANSI B11.0-2023 demands a risk assessment per 5.1—compliance is just one slice.

Beyond THTD: Layered Safeguards That Work

Zero injuries demand hierarchy of controls. Start with THTD for operators, then add light curtains for access zones (ANSI B11.19), interlocked guards for maintenance, and presence-sensing mats. I've retrofitted a Fresno juice plant: THTD plus pressure-sensitive mats cut close calls by 70% in year one.

Train relentlessly—OSHA 1910.147 lockout/tagout integrates with ANSI. Audit for defeats: tampered THTDs void compliance. And quantify: Use Pro Shield-style LOTO tracking to log deviations, proving risk reduction isn't risk elimination.

Bottom line? ANSI B11.0-2023 THTD compliance guards the operator tripwire, but food and beverage chaos demands full-spectrum defenses. Assess holistically, layer protections, and watch incidents drop—results vary by execution, but the data backs it.