HSE Guide on Hand Protection Purpose Hand protection is essential to prevent injuries caused by cuts, burns, chemicals, sharp objects, vibration, heat, electricity, and manual handling activities. Proper glove selection and safe work practices help reduce workplace accidents and occupational illnesses. Common Hand Hazards Workers may be exposed to: Cuts and punctures from sharp tools or materials Chemical burns and skin irritation Heat and cold exposure Electrical shock Abrasions and blisters Crushing or pinching injuries Biological contamination Vibration-related injuries Types of Hand Protection 1. General Purpose Gloves Used for light material handling and basic protection against dirt and minor abrasions. 2. Cut-Resistant Gloves Used when handling: Sharp metals Glass Blades Steel materials 3. Chemical-Resistant Gloves Used during: Chemical handling Cleaning operations Fuel or solvent work Common materials: Nitrile Neoprene PVC Rubber 4. Heat-Resistant Glove...
20-Storey High-Rise Water Supply System
Why Pressure Zoning is Critical in Tall Buildings In high-rise buildings, a single pressure line is never enough. As elevation increases, static pressure differences between lower and upper floors create major hydraulic imbalance. To maintain safe operating pressure, buildings are divided into multiple pressure zones, each served by an independent pump set and dedicated riser. ✦ System Configuration (20-Storey Example) • Zone-1 (Low Zone) → 1st to 7th Floor ✓ Head Requirement: ~20–30 m • Zone-2 (Mid Zone) → 8th to 14th Floor ✓ Head Requirement: ~30-40 m • Zone-3 (Top Zone) → 15th to 20th Floor ✓ Head Requirement: ~45-55 m ✦ Key Hydraulic Design Features ‣ Dedicated pump set for each pressure zone ‣ Independent riser for controlled distribution ‣ Isolation valves for maintenance flexibility ‣ NRV / Check valves to prevent backflow ‣ Pressure switches & gauges for monitoring ‣ Gravity supply from terrace OHT ‣ 2 Duty + 1 Standby pump arrangement for redundancy ✦ Important Design Calculations ✓ Total Dynamic Head (TDH) ✓ Static + Friction loss calculation ✓ Residual pressure at remote fixture ✓ Pipe velocity optimization ✓ Simultaneous demand factor ✓ Pump duty point selection ✓ Water hammer & surge protection ✦ Why Pressure Zoning Matters Without zoning: ✗ Lower floors experience excessive pressure ✗ Upper floors suffer poor flow & low pressure ✗ Higher leakage & fixture failures occur With proper zoning: ✓ Balanced residual pressure ✓ Improved pump efficiency ✓ Better fixture performance ✓ Reduced pipe stress ✓ Higher system reliability ✓ Easier maintenance & troubleshooting ✦ Typical Engineering Guidelines ‣ Residual pressure at fixtures: 1-1.5 bar minimum ‣ Recommended pipe velocity: • Suction line → 1-1.5 m/s • Discharge line → 2-3 m/s ‣ Common materials: • HDPE / MS / GI / CPVC depending on application ‣ Booster pumps: • Usually centrifugal multistage pumps with VFD control ✦ Engineering Insight The success of any high-rise plumbing system depends not only on pump capacity, but on how effectively pressure is managed across vertical elevations. Proper zoning is the backbone of hydraulic stability in tall buildings.
Comments
Post a Comment