October 9 Flashcards
Problems in the video of Two-hand trip for a press in a plant
- both flywheels not guarded
- not wearing safety glasses
- has jewelry on
- two buttons are too close to point of operation
- posture is not ergonomic
what are some exemptions from lockout/tagout- for example, if you having to clear excess material is part of the operation, when would you not have to lockout/tagout?
You would have to provide alternative means of protection that are at least as effective
what kinds of machines do you not need a specific procedure for (as far as lockout/tagout goes)
- cord and plug if there’s a single power source and you control it
- small hand tools
describe the saw stop system in the video shown in class, and what a potential problem with it?
the conductivity of the body stops it (quicker than an airbag) - wet materials might accidentally trip it
difference between a mill and a calendar, and what are the stopping controls?
- a mill is horizontally oriented and a calendar is vertically oriented
- stopping controls is a safety trip rod or bar, or you can run a cable along
- the stopping has to stop relative to how fast it is spinning
explain 63 inches per second theme
63 inches per second is how far back you have to be form the point of operation - related to the stopping time of the device or the cycle time - if it takes 1 second to stop, you must be 63 inches back
Let go threshold?
it is 10-15 mA - at this “let go” threshold, muscles clench up and you cant let go
how does a fuse or circuit breaker protect a person?
- it doesn’t protect you, it protects the equipment
- a ground fault circuit interrupter (GFCI) protects the person - it measures outgoing amp current to incoming amp current, and if there’s a difference, it shuts off very quickly
Case Study - the station nightclub in west warwick
- were doing a concert at the nightclub
- used foam acoustics (not flame retardant) - sparks caused flame in the foam, but many people thought it was part of the show
the fire tetrahedron
the removal of any one element extinguishes the fire:
- oxygen
- fuel
- heat
Auto-ignition temperature definition
the temperature at which material will spontaneously ignite. many materials undergo thermal decomposition before the auto-ignition temperature is reached
Fire Definition
a chemical reaction in which a combustible material is rapidly oxidized and heat is produced
exothermic definition
a reaction that gives off heat and proceeds without encouragement
explosive limits definition
the range of atmospheric concentrations over which, if ignited, an explosion will occur
Lower Explosive Limit (LEL)
the lowest percentage of concentration in air that a mixture of material, if ignited, will explode - below this, mixture is too “lean” to explode
