Compressed Air Pipe Data

Detailed Description

The shared PipeData shape stores one value for each supported nominal pipe size. The stored value depends on the calculation context:

• In the air system capacity calculation, each value is contained pipe volume in ft3.
• In the air velocity calculation, each value is calculated air velocity in ft/s.

The tables below document the implementation coefficients used to convert pipe lengths to contained volume and to evaluate velocity by nominal pipe size.

Pipe Volume

---

Contained pipe volume for one nominal pipe size.

The length constructor multiplies each entered pipe length by a per-foot volume coefficient for that nominal pipe size.

\begin{equation}\label{eq:pipe-data-volume} V_i = L_i \cdot c_i \end{equation}

Symbols

\(V_i\)	Contained pipe volume for nominal size i \([\unit{ \cubicFoot}]\)
\(L_i\)	Installed pipe length for nominal size i \([\unit{ \foot}]\)
\(c_i\)	Pipe volume coefficient for nominal size i \([\unit{ \cubicFoot\per\foot}]\)

Total Pipe Volume

---

Total contained pipe volume across all supported nominal pipe sizes.

The total pipe volume is the sum of the per-size volumes calculated by Pipe Volume Formula.

\begin{equation}\label{eq:pipe-data-total-volume} V_{pipe,total} = \sum_i V_i \end{equation}

Symbols

\(V_{pipe,total}\)	Total contained pipe volume \([\unit{ \cubicFoot}]\)
\(V_i\)	Contained pipe volume for nominal size i \([\unit{ \cubicFoot}]\)

Implementation Tables

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Coefficients and internal areas used by the shared pipe data implementation.

The volume coefficients are used by the length constructor. The internal areas are passed to the air velocity formula. The existing source does not identify the external standard behind these values, so they are documented here as implementation tables.

Nominal pipe size	Volume coefficient \([\unit{\cubicFoot\per\foot}]\)	Internal area \([\unit{\inch\squared}]\)
1/2 in	0.0021	0.3
3/4 in	0.0037	0.53
1 in	0.006	0.86
1-1/4 in	0.0104	1.5
1-1/2 in	0.0141	2.04
2 in	0.0233	3.36
2-1/2 in	0.0333	4.79
3 in	0.0513	7.39
3-1/2 in	0.0687	9.89
4 in	0.0884	12.73
5 in	0.1389	20
6 in	0.2006	28.89
8 in	0.3442	50.02
10 in	0.5476	78.85
12 in	0.7763	111.9
14 in	0.9354	135.3
16 in	1.223	176.7
18 in	1.555	224
20 in	1.926	278
24 in	2.793	402.10

Modules
	Pipe Volume Formula
	Contained pipe volume for one nominal pipe size.
	Total Pipe Volume Formula
	Total contained pipe volume across all supported nominal pipe sizes.
	Pipe Data Implementation Tables
	Coefficients and internal areas used by the shared pipe data implementation.

Files
file	pipe_data.h
	Shared pipe-size data shape for compressed air capacity and velocity calculations.

Namespaces
namespace	pipe_data
	Shared pipe data for compressed air calculators.

Classes
struct	pipe_data::PipeData
	Per-size values for standard compressed air pipe sizes. More...