liminfoPiping Reference
Free reference guide: Piping Reference
About Piping Reference
The Piping Engineering Reference is a searchable guide covering essential piping data for process, mechanical, and plant engineers. It includes NPS 1/2" through 24" pipe dimensions with wall thickness and inner diameter by schedule (Sch 5S through XXS), plus material specifications for ASTM A106, A312, A335, and API 5L line pipe.
This reference documents ASME B16.5 flange pressure-temperature ratings from Class 150 to Class 2500, including maximum allowable pressure tables for carbon steel (A105) and stainless steel (F304) at various temperatures, flange face types (RF, RTJ, FF), and connection types (WN, SO, SW, BL).
Flow calculation formulas include Darcy-Weisbach pipe friction loss, Hazen-Williams for water supply, and recommended flow velocities for liquids and gases. Fitting data covers elbows, tees, and reducers with equivalent lengths, while gasket and valve sections detail SWG/RTJ selection and Cv/Kv flow coefficient calculations.
Key Features
- NPS 1/2" to 24" pipe dimension tables with OD, wall thickness, and ID by schedule (Sch 5S to XXS)
- ASTM A106/A312/A335 and API 5L material grade specifications with yield/tensile strength and temperature ranges
- ASME B16.5 flange pressure-temperature ratings for Class 150 through Class 2500 in carbon and stainless steel
- Flange face types (RF, RTJ, FF, TG) and connection types (WN, SO, SW, BL, LJ, TH) with application guidance
- Darcy-Weisbach and Hazen-Williams flow formulas with Reynolds number and Colebrook equation for turbulent flow
- Recommended flow velocity ranges for water, oil, steam, compressed air, and natural gas piping
- Elbow, tee, and reducer fitting specifications with equivalent length (L/D) values per ASME B16.9
- Gasket selection guide (SWG, RTJ, PTFE) with m/y factors and valve Cv/Kv flow coefficient formulas
Frequently Asked Questions
What pipe dimensions does this reference include?
This reference covers NPS 1/2" (DN 15) through NPS 24" (DN 600) with outer diameter, wall thickness, and inner diameter for schedules Sch 5S, 10S, 40, 80, 120, 160, and XXS. For example, NPS 4" (DN 100) has an OD of 114.3mm with Sch 40 wall thickness of 6.02mm and ID of 102.26mm. For pipes 14" and above, the OD equals the NPS in inches.
What is the difference between ASTM A106 and A312 pipe?
ASTM A106 is seamless carbon steel pipe for high-temperature service (-29 to 427 degrees C), with Grade B being most common at 240 MPa yield and 415 MPa tensile strength. ASTM A312 covers seamless and welded austenitic stainless steel pipe (TP304, 316, 321, 347) for temperatures from -254 to 816 degrees C, offering superior corrosion resistance for chemical and cryogenic applications.
How do ASME flange Class ratings work?
ASME B16.5 defines flange pressure-temperature ratings from Class 150 (PN 20) to Class 2500 (PN 420). Maximum allowable pressure decreases with temperature. For example, Class 150 carbon steel (A105) is rated at 19.6 bar at 38 degrees C but only 10.2 bar at 400 degrees C. Higher classes like 600, 900, and 1500 use RTJ gaskets for improved high-pressure sealing.
When should I use a Weld Neck vs Slip-On flange?
Weld Neck (WN) flanges are optimal for high-pressure and high-temperature service because the tapered hub provides excellent stress distribution. Slip-On (SO) flanges suit low-pressure general applications and are easier to align. Socket Weld (SW) flanges are used for small bore piping, while Blind (BL) flanges close pipe ends and Lap Joint (LJ) flanges allow frequent disassembly.
How do I calculate pipe friction loss using Darcy-Weisbach?
The Darcy-Weisbach equation is hf = f x (L/D) x (V squared / 2g), where f is the friction factor from the Moody chart, L is pipe length, D is inner diameter, V is velocity, and g is gravity. For laminar flow (Re < 2100), f = 64/Re. For turbulent flow (Re > 4000), use the Colebrook equation: 1/sqrt(f) = -2log(epsilon/3.7D + 2.51/Re*sqrt(f)).
What are the recommended flow velocities for different fluids?
For water pump discharge: 1.5-3.0 m/s, pump suction: 0.5-1.5 m/s. Oil: 0.5-1.5 m/s. Saturated steam: 25-35 m/s, superheated steam: 35-60 m/s. Compressed air: 15-25 m/s. Natural gas at low pressure: 15-25 m/s. These economic velocities help determine optimal pipe diameter for balancing installation cost and operating pressure drop.
How do I select the right gasket type for my application?
For Class 150-300 general service, use non-metallic sheet gaskets (rubber, PTFE). Spiral Wound Gaskets (SWG) with graphite filler are most common for Class 150-900 and steam up to 300 degrees C. Ring Type Joint (RTJ) gaskets in soft iron or Inconel are required for Class 600-2500 high-pressure service. The gasket factor m and seating stress y determine bolt load requirements.
What is the Cv/Kv valve flow coefficient and how do I calculate flow?
Cv is the flow rate in GPM of 60 degrees F water through a valve at 1 psi pressure drop. Kv is the metric equivalent in m3/h at 1 bar drop (Kv = 0.865 x Cv). For liquid flow: Q = Cv x sqrt(deltaP / SG). For gas flow: Q = 963 x Cv x P1 x sqrt(x / (T x SG x Z)), where x = deltaP/P1, P1 is inlet pressure in psia, and T is absolute temperature in Rankine.