FIRE PRESSURE CALCULATION FOR HIGH-RISE BUILDINGS Fire pressure calculation in high‑rise buildings is primarily determined by static head (height), friction losses, and residual pressure requirements at the most remote outlet. For example, a 30‑story tower (~310 ft) requires about 135 psi just to overcome elevation, with total pump discharge often reaching 260–290 psi plus a safety margin. NFPA 14 mandates at least 100 psi at the topmost standpipe outlet. 🔑 Key Components of Fire Pressure Calculation Static Head Pressure required to lift water vertically. Formula: 0.433 psi per foot of elevation (≈ 1 bar per 10 m). Example: 200 m building → ~290 psi static pressure at base. Friction Loss Caused by pipe length, diameter, fittings, and flow rate. Must be added to static head to determine total pump discharge. Residual Pressure NFPA 14 requires 100 psi at the most remote standpipe outlet . Sprinkler systems may have lower requirements, but standpipes govern in high‑rise design. Sa...
REFRIGERANT FLOW CONTROLS IN HVACR SYSTEMS Understanding Metering Devices, Applications, Advantages, and System Protection Every vapor-compression HVACR system requires a method of controlling refrigerant flow between the high-pressure and low-pressure sides of the system. This component is commonly called a: Refrigerant control Metering device Expansion device Refrigerant flow-control device The metering device performs two essential functions: It creates the pressure drop that allows high-pressure liquid refrigerant to enter the lower-pressure evaporator. It regulates the quantity of refrigerant entering the evaporator so that the coil can absorb heat without starving, flooding, or returning excessive liquid refrigerant to the compressor. Historically, six major types of refrigerant controls have been associated with HVACR system design: Thermostatic Expansion Valve Capillary Tube Automatic Expansion Valve High-Pressure-Side Float Valve Low-Pressure-Side Float Valve Electronic ...