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Egypt Engineering Consultant Mechanical study materials
Egypt Engineering Consultant Mechanical study resources

Egypt Engineering Consultant Mechanical: Plumbing, Drainage and Fire Protection Systems

Egypt Engineering Consultant Mechanical · Work through your exam, one topic at a time.

All guide sections

Plumbing, Drainage and Fire Protection Systems

What the exam tests

This domain covers potable water supply, drainage and venting, stormwater, and fire suppression. The exam tests fixture-unit demand, trap and vent design, pump selection, sprinkler density and area, standpipe and hydrant flows, and fire-water tank sizing under Egyptian plumbing and fire codes.

Core rules

  • Fixture units (FU) convert to probable demand; not all fixtures run together. Use Hunter’s curve or the code table, and add flush-valve loads separately because they are short-duration and high-peak.
  • Each fixture needs a trap with a 50–75 mm seal and proper venting. Check stack-venting limits and branch length; a lost seal admits sewer gas.
  • Drainage slopes are typically 1–2 % for 100–150 mm pipes. Avoid long horizontal branches and sharp bends; use sweep fittings and cleanouts at changes of direction.
  • Supply pressure should be about 1–3 bar at fixtures. Above 3–4 bar use a pressure-reducing valve; below it use a break tank and duplex booster set.
  • Fire design: classify the hazard, then apply density × area of operation plus hose allowance. Tank volume equals fire-pump flow × duration. The fire pump is dedicated and has a test header and jockey pump.
  • Select pumps near the best efficiency point; check NPSH, runout and standby duty.

Worked example

A light-hazard sprinkler area is 200 m² at 6 mm/min. That is 1.2 m³/min, or 20 L/s. Add a 10 L/s hose allowance, giving 30 L/s. For a 60-minute duration, tank volume is 30 × 60 × 60 = 108,000 L, or 108 m³. If the occupancy is ordinary hazard and the code requires 90 minutes, the same flow needs 162 m³. The classification, not the pump, drives the tank.

Traps

Adding every fixture flow instead of using FU demand; omitting flush-valve peaks; forgetting the hose allowance; using a 60-minute duration where the code requires 90; losing a trap seal through missing venting; selecting a pump at shutoff head rather than duty point; ignoring the authority having jurisdiction for fire approval.

Key points

  • Convert fixtures to FU and use probable simultaneous demand.
  • Trap seals are 50–75 mm and must be vented.
  • Fire tank volume = pump flow × duration, including hose allowance.
  • Hazard classification sets sprinkler density, area and duration.
  • Check pump duty point, NPSH and standby arrangement.