Engineering Resources
Engineering Blog
In-depth guides, conversion cheat sheets, and industry best practices for HVAC, compressed air, pump systems, and process engineers.
Compressed Air System Design: SCFM, ACFM, ICFM — The Complete Engineer's Guide
Definitive guide to SCFM, ACFM, and ICFM conversions for compressed air system design. Includes altitude correction tables, pipe sizing methodology, compressor selection checklist, and worked examples.
HVACHVAC Engineer's Unit Conversion Cheat Sheet
Complete HVAC unit conversion reference: BTU/hr to kW, tons to kW, CFM to m³/h, ACH, velocity, sensible and latent heat — with formula tables, worked examples, and calculator links.
Gas FlowCompressed Air Piping Design: Sizing, Pressure Drop & Material Selection
Complete guide to compressed air piping design. Pipe sizing from ACFM, pressure drop calculations (Darcy-Weisbach and equivalent length), velocity limits by material, loop vs dead-end layout, and condensate management.
PumpPump Head Curve Basics: Understanding Head, Flow, System Curves & NPSH
Complete guide to reading and applying centrifugal pump curves. Covers head vs pressure, system curve construction, NPSH margin, affinity laws, VFD operation, and parallel/series pump configurations with worked examples.
HVACHVAC Load Calculation Guide: Manual J, Sensible & Latent Heat Explained
Complete guide to HVAC load calculations. Covers Manual J and ASHRAE RTS methodology, envelope heat gains, internal loads, ventilation, sensible/latent split, with a fully worked example for a 5,000 ft² commercial office.
PressurePressure Units: A Practitioner's Guide for Engineers
Complete engineering reference for pressure units: psi, bar, kPa, MPa, atm, inHg, inH₂O, mmHg, torr. Gauge vs absolute explained with altitude examples, vacuum range classification, and conversion shortcuts for daily industrial use.
Fluid FlowVolumetric Flow Rate Explained: Formulas, Units & Conversions for Engineers
Complete engineering guide to volumetric flow rate: Q = A × v and Q = ṁ/ρ formulas, common units (CFM, GPM, L/s, m³/h, LPM), mass-to-volumetric conversion, standard vs actual conditions, and worked examples.
HVACHVAC Duct Sizing: CFM Chart, Velocity & Ductwork Design Calculator Guide
Complete HVAC duct sizing reference: CFM duct chart for round and rectangular ducts, velocity limits by application, friction rate method, duct sizing formulas (Q = A × v), and free calculator tools for engineers.
HVACHow to Calculate Relative Humidity: Wet Bulb, Dry Bulb, Dew Point & Psychrometrics
Complete guide to humidity calculation for HVAC and process engineers. Wet bulb to relative humidity formula, psychrometric chart reference, dew point calculation from temperature and RH.
EnergyPower & Energy Conversion Guide: kW, HP, BTU/hr, Ton, Therm & MBTU
Complete power and energy unit conversion reference for mechanical and HVAC engineers. Convert kW to HP, kW to BTU/hr, HP to watts, tons of refrigeration to kW, kWh to BTU, therms to BTU, and MBTU to kWh.
Gas FlowSCFM vs CFM: The Complete Comparison Guide for Compressed Air Engineers
What is the difference between SCFM and CFM in compressed air systems? Covers the 7.8:1 ratio at 100 psig, altitude correction, and the pipe sizing error to avoid.
Gas FlowWhat Is SCFM? Standard Cubic Feet per Minute — Complete Definition & Engineering Reference
SCFM definition, formula, and industrial applications. SCFM = Standard Cubic Feet per Minute at 14.7 psia and 68°F. Learn SCFM vs CFM vs ICFM, CAGI vs ISO standards.
Fluid FlowSpecific Gravity to Density: The Engineer's Complete Conversion Guide
How to convert specific gravity to density (and back). SG = density / 1000 kg/m³ or 62.4 lb/ft³. Includes complete density reference tables and worked pump power calculations.
EnergyEUR/MWh to USD/MMBTU: Energy Price Conversion for International Power & Gas Markets
How to convert EUR/MWh to USD/MMBtu for LNG trading, power plant economics, and industrial energy procurement.
TemperatureRankine Temperature Scale: What Every Engineer Needs to Know About °R
Complete guide to the Rankine (°R) temperature scale. °R = °F + 459.67. Covers the physics of the absolute zero offset, US steam tables, gas turbine performance, and cryogenic LNG applications.
PressurePSI to Inches of Water Column: The Low-Pressure Engineer's Guide
Complete guide to psi and inches of water column (inWC / inH₂O) conversion. 1 psi = 27.68 inH₂O. Covers HVAC duct static pressure, cleanroom differentials, gas piping pressure drop.
EnergyTherms, kWh, MMBTU, and BTU: Making Sense of Energy Billing Units
Master therms to kWh, MMBTU to kWh, BTU to MMBTU, and other energy unit conversions. Compare natural gas vs electric heating costs with real utility rate examples.
PressureTorr and mmHg: The Engineer's Guide to Pressure & Vacuum Measurement
Complete guide to Torr and mmHg pressure units. 1 Torr = 1 mmHg = 0.01934 psi = 1/760 atm. Covers vacuum pump specifications, semiconductor processes, and lyophilization.
Densitykg/m³ to lb/ft³ Density Conversion: The Fluid Engineer's Complete Reference
Master kg/m³ to lb/ft³ density conversions. 1 kg/m³ = 0.062428 lb/ft³. Complete density table for water, air, fuels, metals, and process fluids.
HVACMBH to kW and BTU/hr to kW: The HVAC Engineer's Power Conversion Guide
Master MBH to kW, BTU/hr to kW, and kW to MBH conversions. Complete boiler and chiller power conversion reference with ASME boiler categories.
DensityBrix to Specific Gravity: The Winemaker, Brewer & Process Engineer's Complete Guide
Master Brix to SG conversion for winemaking, brewing, sugar refining, and food processing. ICUMSA Method GS4-13, ASBC standards, refractometer corrections, and worked industry examples.
DensityPlato, Brix, Balling: The History of Three Sugar Concentration Scales
Why are there three names for the same sugar scale? Historical origins from Balling (1850) to Brix (1854) to Plato (1918). Modern industry usage map, numerical differences, and why it matters for compliance.
DensityBrewing Math: Original Gravity, Final Gravity & ABV Calculation
Complete brewing math reference: OG, FG, apparent vs real extract, attenuation, ABV formulas per ASBC Beer-2B, and refractometer correction.
EnergySteam Boiler vs Hot Water Boiler: The Engineer's Selection Guide
ASME code analysis (15 psig threshold), application matrix, total cost of ownership, and decision framework for commercial and industrial boiler selection.
ValveControl Valve Sizing: The ISA 75.01 Equations Explained
Complete ISA 75.01 walkthrough: liquid, gas, and steam Cv formulas. Choked flow detection, viscosity correction (F_R), Kv vs Cv, and common errors in commercial calculators.
ValveValve Authority and Rangeability: Why β Matters in Control Valve Performance
Valve authority β analysis. When β < 0.25 fails, how to fix low-authority situations, and the 50% rule of thumb per Fisher handbook.
ValveValve Characteristic Curves: Linear, Equal Percentage, Quick Opening
Inherent vs installed characteristics, when to use linear, equal-percentage, or quick opening. The system curve interaction problem and when to use which.
ValveCavitation, Flashing, and Choked Flow in Control Valves
When Cv sizing goes wrong. The σ and Kc methods, ISA 75.01 prediction techniques, and real damage case studies.
ValveControl Valve Noise Prediction: IEC 60534-8-3 and the LpA Method
Aerodynamic vs hydrodynamic noise. The LpA method, OSHA 85 dBA threshold, and noise attenuation options.
Fluid MechanicsReynolds Number Explained: The Engineer's Complete Guide to Re = ρVD/μ
Complete Reynolds number reference: every form (ρVD/μ, VD/ν, 4ṁ/πDμ), all units, boundary analysis, and worked examples across 6 industries.
Fluid MechanicsFlow Regimes: Laminar, Transitional, and Turbulent — When Each Matters
Boundary analysis (2,300 vs 4,000 vs 2,000), Reynolds' 1883 experiment, when each regime matters in industry, and verification methods.
Fluid MechanicsMoody Chart and Friction Factor: Colebrook-White vs Swamee-Jain Explained
The 1944 Moody chart, the 1939 Colebrook-White equation, the 1976 Swamee-Jain explicit approximation, and the Darcy vs Fanning distinction.
Fluid MechanicsHydraulic Diameter: Reynolds Number and Friction in Non-Circular Ducts
Dh = 4A/P for rectangular ducts, annuli, and finned tubes. Aspect ratio effects on friction. When hydraulic diameter applies and when it doesn't.
Fluid MechanicsReynolds Number in Compressible Flow: Mach Number, and When Re Alone Isn't Enough
M > 0.3 transitions. Re + Ma quadrant analysis. Fanno flow lines, choking in compressible service, when Re alone misleads.
Fluid MechanicsEntrance Length and Developed Flow: When Re Alone Isn't Enough
L_e = 0.06 Re D (laminar), 10-60 D (turbulent). When entry length matters (instrument connections, headers) and when it doesn't.
Fluid MechanicsDimensional Analysis and Similitude: Why Re Matters for Scale-Up
Buckingham Pi, the primary dimensionless groups (Re, Fr, Eu, We, Ma, Pr), and scale-up pitfalls in pipe flow models.
SteamSteam Quality Explained: Wet Steam, Dryness Fraction, and Enthalpy
Complete guide to steam quality (x). IAPWS-IF97 reference, throttling calorimeter method, and when poor steam quality causes corrosion.
SteamBoiler Efficiency: Direct Method vs Indirect (Heat Loss) Method
ASME PTC 4 walkthrough. Direct input-output method vs indirect heat loss method. Flue gas analysis, typical loss ranges by fuel, and field audit procedure.
SteamSteam Tables Deep Dive: Reading IAPWS-IF97 for Engineers
IAPWS-IF97 region map (1-5), how to read a Mollier diagram, saturated vs superheated, common lookup mistakes, and modern steam property software.
SteamSteam System Design: Header Sizing, Condensate Return, and Steam Traps
Practical steam system engineering. Header sizing rules, flash steam recovery, condensate return pump sizing, and steam trap selection (inverted bucket vs float vs thermostatic).