Precast Concrete Industry – Application Series: 2 of 5 Gravel Pits: Confined Space

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Precast Concrete Industry – Application Series: 2 of 5

Gravel Pits: Confined Space – Trapped Key Interlock Safety Solutions

4.8 million confined space incidents a year are logged with OSHA

Τhe storage of aggregate for various usage can lead to the potential risk to personnel involving engulfment within hoppers (confined space) and loss of materials due to incorrect materials loading. Protecting workers from confined space hazards that can occur during maintenance, cleaning, filling, and unloading of hoppers is critical within a gravel pit.

In 2020, according to the MAYDAY-FORMATION website, there were 10 fatal accidents and 20 serious accidents in France related to confined spaces

Interlocking access doors/gates around conveyor systems and hoppers will ensure that entry can only be gained after the power has been isolated and residual energy has ceased. Understanding the access points, partial or full body, will help determine the best interlocking solution to safely manage access to the hoppers and surrounding areas that could pose a confined space hazard.

60% of confined space fatalities are rescuers – Let’s change the statistics and enhance your safety!

Trapped key interlock safety solutions ensure a pre-determined sequence of operations each & every time. While LOTO provides a visual warning and identifies hazards, a TKI solution physically prevents a specific set of actions from being performed until previous action(s) have been fully completed!

Common trapped key interlock solution interlocking conveyor system with multiple access points and hopper doors to mitigate confined space hazards:


Step 1: Power Isolation MS Bolt Lock installed on main breaker for conveyor

Step 2: Multiple Entry Points STI TMEC key exchange box for access to multiple hopper access doors

Step 3: Safe Access MS30LTC* access lock installed on hopper doors

Download the pdf version of this second part of our Precast Concrete Application Series focusing on how trapped key interlocking solutions can help mitigate confined space hazards.