Typical insulation thicknesses for VRF and split refrigerant pipes, a quick surface-temperature check against the dew point with a worked 3/4″ example, and the installation rules that matter most.
Refrigerant Pipe Insulation: Thickness and Condensation Read More »
How to size fire alarm standby batteries: the formula, which standby and alarm durations apply under EN 54 practice and NFPA 72, and a worked example from currents to battery size.
Fire Alarm Standby Battery Calculation Read More »
The method behind natural gas pipe sizing, from appliance heat input to gas flow and the code table, and the safety points that matter more than the size.
Natural Gas Pipe Sizing Basics Read More »
Size a basement sump pump and pit: peak inflow, rising main velocity, the V = Qp × T ÷ 4 working volume and the level stack, with a worked example.
Sump Pump and Pit Sizing for Basements Read More »
Size a hot water cylinder from peak demand, heater recovery and usable volume, with a worked sports changing room example and rule-of-thumb volumes.
Hot Water Storage Cylinder Sizing Read More »
Why quick-closing valves cause water hammer, how big the surge is (Δp = ρ·a·Δv) and how to size and place arrestors, with a worked solenoid valve example.
Water Hammer: Causes and Arrestor Sizing Read More »
Estimate the fan duty of a pressurised stair from closed-door leakage and open-door velocity, then check the door opening force and relief.
Stair Pressurisation: Quick Airflow Design Read More »
Heat flux, surface limits, flow temperature and loop lengths for wet underfloor heating, with a worked living room and the bathroom that sets the flow temperature.
Underfloor Heating: Quick Design Rules Read More »
Catalogue radiator outputs are for 75/65/20 °C; at heat-pump temperatures you need two to three times more. Here are the factors and a worked room.
Radiator Sizing: Correction Factors for Low Temperatures Read More »
Find where the heat pump stops coping on its own: a straight-line load and capacity check gives the bivalent point and the backup heater size in minutes.
Heat Pump Sizing and the Bivalent Point Read More »