Occupational Safety, Health and Environmental Practices
What the exam tests here
Safe work around water, electricity and agrochemicals, plus the environmental duties that come with intensive irrigation.
Core rules
- Electrical: earth the pump and panel, use ELCB/MCB protection, never handle a panel with wet hands, keep joints above ground in a sealed enclosure, and isolate the supply before opening a starter.
- Backflow protection: fit a non-return valve and maintain an air gap between the water source and any fertilizer line. Fertigation must never be able to siphon chemicals into a well, canal or public supply.
- Chemicals: goggles, gloves, apron and mask; always add acid slowly to water, never water to acid; store acids and chlorine separately in labelled, ventilated, locked containers.
- First aid for acid on skin: flush with plenty of clean water for at least 15 minutes and seek medical help.
- Trenching: check for buried cables and pipes, batter trench walls in loose soil, and barricade open trenches near paths.
- Environment: schedule to avoid deep percolation and nitrate leaching, keep backwash water on the field rather than in a drain, recycle drip tape and plastic, and prefer solar pumps where head and duty suit.
Worked example
A technician wants to inject muriatic acid through a venturi with no non-return valve and the pump switched off. Reasoning: with the pump off, the line can back-siphon into the well, and acid in a drinking-water source is a serious hazard. Correct sequence: fit the non-return valve, run the pump, inject acid downstream of the pump but upstream of the filter with the system running, wear full PPE, flush afterwards, and record the dose.
Traps that cost marks
- Assuming a check valve alone is enough without an air gap.
- Mixing chlorine and acid.
- Leaving an open trench unbarricaded overnight.
Quick recall
Earth, ELCB, non-return valve, PPE, and acid into water - never water into acid.