Piping & Utility Systems

Common materials include carbon steel (black/galvanized), stainless steel (304/316), copper (types L, K), CPVC, PPR, HDPE, and lined/coated pipes. Selection depends on fluid type, temperature, pressure, and corrosion considerations.

Pipe sizing considers flow rate (GPM), velocity limits (2-4 fps for chilled water), pressure drop per 100 ft (0.5-4 ft H2O), available pump head, noise criteria, and future expansion. ASHRAE guidelines and pump curves guide optimization.

Hydraulic balancing ensures each terminal unit receives design flow by adjusting balancing valves. It prevents over/under-flow, reduces pumping energy, ensures proper heat transfer, and maintains system efficiency and comfort.

Expansion joints accommodate thermal expansion/contraction and movement. Required in long straight runs, between building sections, at equipment connections, and where movement exceeds pipe material's flexibility. Types include bellows, slip, and rubber expansion joints.

Piping insulation prevents heat gain/loss (energy conservation), controls condensation (chilled water/dew point), provides personnel protection (hot pipes), reduces noise, and meets code requirements. Materials include elastomeric, fiberglass, mineral wool, and PIR/PUF.

Common valves include ball valves (isolation), gate valves (full flow), globe valves (throttling), butterfly valves (large diameter), check valves (prevent backflow), balancing valves (flow control), pressure relief valves, and control valves (automated flow regulation).

Common configurations include direct return (simpler, less balanced), reverse return (balanced flow), primary-secondary (decoupled pumping), variable primary flow (energy efficient), and hybrid systems combining multiple approaches.

Pressure drops include friction losses (Darcy-Weisbach/Hazen-Williams equations), fitting/valve losses (equivalent length/K-factor method), equipment losses (chillers, coils, heat exchangers), elevation changes, and safety factors (15-25%).

Water treatment prevents corrosion, scale formation, biological growth (legionella), and fouling. Includes chemical treatment (corrosion inhibitors, biocides, scale controllers), filtration, side-stream cleaning, and continuous monitoring/maintenance.

Testing includes hydrostatic pressure testing (1.5x design pressure), leak testing, flushing/cleaning (velocity-3 fps), chemical cleaning, passivation (stainless steel), flow/pressure balancing verification, and documentation for commissioning.

Pipe supports prevent sagging, control movement, and manage stress. Spacing depends on pipe material, size, fluid, temperature, and codes. Steel pipes: 10-20 ft, copper: 6-12 ft, plastic: 3-8 ft. Types include hangers, rollers, guides, anchors, and spring supports.

Chilled water: Lower temperatures (40-45°F supply), closed system, higher ΔT (10-15°F), corrosion protection critical, condensation prevention. Condenser water: Higher temperatures (85-95°F), open/closed system, lower ΔT (10°F), biological control, scaling prevention, larger pipe sizes typically.