Correction Formulae & Sizing

Call 714.891.0008

Gas Flowmeter Sizing Click Here To Download A Printable Version
Variable area flowmeters suitable for liquid service have a capacity rating based on water at 70° Fahrenheit. Flowmeters suitable
for gas service have a capacity rating based on air at STP (70°F, 14.7 PSIA) conditions. The correction factors listed below are
used to calculate the flow capacity when using a liquid other than water or a gas other than air at STP conditions.

GAS CORRECTION FORMULA

Air Equivalent Flow Rate =

Customer Gas Flow Rate
X Gas Correction Factor

Step 1:

Convert Customer Gas Flow Rate unit of measure to a standard unit of measure for air flow (SCFM or SCCM).

Step 2:

Calculate Gas Correction Factor from given values.

Step 3:

Calculate the product of the Air Equivalent Flow Rate from the Customer Gas Flow Rate and the Gas Correction Factor.

Step 4:

Calculate the maximum or minimum flow rate for the customer’s conditions.

Step 1: Convert Customer Gas Flow Rate unit of measure to
a standardunit of measure for air flow

Customer Gas Flow Rate ________________
Converted Gas Flow Rate ________________ SCFM / SCCM

Gas Flow Rate Conversions
From	To SCFM	From	To SCCM
SCFH	Divide by 60	SCFM	Multiply by 28,317
SCIM	Divide by 1,728	SCFH	Multiply by 472
SLPH	Divide by 28.317	SCIM	Multiply by 16.39
SM³/MIN	Multiply by 35.31	SLPM	Multiply by 1,000
SM³/HR	Multiply by 0.5885	SLPH	Multiply by 16.67
NM³/MIN	Multiply by 37.99	SM³/MIN	Multiply by 1,000,000
NM³/HR	Multiply by 0.6331	SM³/HR	Multiply by 16,667
SCCM	Divide by 28,317	NM³/MIN	Multiply by 1,075,785
KG/MIN	Multiply by (29.39 ÷ SpGr)	NM³/HR	Multiply by 17,929
KG/HR	Multiply by (0.49 ÷ SpGr)	KG/MIN	Multiply by (832,000 ÷ SpGr)
LBS/MIN	Multiply by (13.33 ÷ SpGr)	KG/HR	Multiply by (13,876 ÷ SpGr)
LBS/HR	Multiply by(0.2222 ÷ SpGr)	LBS/MIN	Multiply by (377,500 ÷ SpGr)
LBS/DAY	Multiply by (0.00926 ÷ SpGr)	LBS/HR	Multiply by (6,292 ÷ SpGr)
ACFM	Multiply by [[(Operating PSIG+14.7)(530)] ÷ [(14.7)(Operating °F+460)]]

Step 2: Calculate Gas Correction Factor from given values

This information is required to size for conditions other than air at STP:
• Operating Temperature: _________°F
• Operating Back Pressure:_________ PSIG
• Specific Gravity of Gas: _________ @STP

Temperature Conversions		Gas Density Conversions
From	To °Fahrenheit	From	To Specific Gravity
°Centigrade	(°C X 1.8) + 32	LBS/FT³	Divide by 0.075
°Kelvin	(°K – 273.15)1.8 + 32	KG/M³	Divide by 1.2
°Rankine	°R – 459.67	MolWt	Divide by 29.0
		g/cm³	Divide by 0.0012

Pressure Conversions
From	To PSIG	From	To PSIG
foot Water	Divide by 2.308	Pa	(Pa÷101,300) X 14.7
Inch Water	Divide by 27.73	PSIA	Minus 14.7
mm Water	Divide by 704	ATM	(ATM X 14.7) – 14.7
inch Hg	Divide by 2.036	Torr	((Torr÷760) X14.7) – 14.7
mm Hg	Divide by 51.7	Bars	((Bars÷1.013) X14.7) – 14.7
kg/cm²	Multiply by 14.228	Millibar	((Millibars÷1013) X 14.7) –14.7
kPa	(kPa÷101.3) X 14.7

Gas Correction Factor (GCF) formula:

GCF = _________________

Step 3: Determine the Air Equivalent Flow Rate.

Air Equivalent Flow Rate = Customer Gas Flow Rate x Gas Correction Factor
Air Equivalent Flow Rate = ____________________

Step 4: Calculate the maximum or minimum flow rate for the
customer’s conditions (Customer Gas Flow Rate Scale)

Customer Gas Flow Rate Scale = Catalog Flow Rate ÷ Gas Correction Factor
Customer Gas Flow Rate Scale = ______________________

Liquid Flowmeter Sizing Click Here To Download A Printable Version
Variable area flowmeters suitable for liquid service have a capacity rating based on water at 70°Fahrenheit. Flowmeters suitable for gas service have a capacity rating based on air at STP (70°F, 14.7 PSIA) conditions. The correction factors listed below are used to calculate the flow capacity when using a liquid other than water or a gas other than air at STP conditions.

LIQUID CORRECTION FORMULA

Water Equivalent Flow Rate =

Customer Liquid Flow Rate
X Liquid Correction Factor

Step 1:

Convert Customer Liquid Flow Rate unit of measure to a standard unit of measure for water flow (GPM or CC/MIN).

Step 2:

Calculate Liquid Specific GravityCorrection Factor from given values.

Step 3:

Determine the Water Equivalent Flow Rate from the product of the Customer Liquid Flow Rate and the Liquid Correction Factor.

Step 4:

Calculate the maximum or minimum flow rate for the customer’s conditions.

Step 1: Convert Customer Liquid Flow Rate unit of measure
to a standard unit of measure for water flow.

Customer Liquid Flow Rate ________________
Converted Gas Flow Rate _________________GPM / CC/MIN

Liquid Flow Rate Conversions
From	To GPM	From	To CC/MIN
GPH	Divide by 60	GPM	Multiply by 3,785
CC/MIN	Divide by 3,785	GPH	Multiply by 63.08
CC/HR	Divide by 227,100	CC/HR	Divide by 60
LPM	Multiply by 3.785	LPM	Multiply by 1,000
LPH	Multiply by 227.1	LPH	Multiply by 16.67
M³/MIN	Multiply by 264.2	M³/MIN	Multiply by 1,000,000
M³/HR	Multiply by 4.402	M³/HR	Multiply by 16,667
PINTS/MIN	Divide by 8	PINTS/MIN	Multiply by 473.1
FT³/MIN	Multiply by 7.48	FT³/MIN	Multiply by 28,320
FT³/HR	Divide by 8.021	FT³/HR	Multiply by 472
KG/MIN	Multiply by (0.264 ÷ SpGr)	KG/MIN	Multiply by (1,000 ÷ SpGr)
KG/HR	Divide by (227 X SpGr)	KG/HR	Multiply by (16.67 ÷ SpGr)
LBS/MIN	Divide by (8.347 X SpGr)	LBS/MIN	Multiply by (453.6 ÷ SpGr)
LBS/HR	Divide by (500.8 X SpGr)	LBS/HR	Multiply by (7.56 ÷ Spgr)
GMS/MIN	Divide by (3,785 X SpGr)	GMS/MIN	Divide by SpGr
GMS/HR	Divide by (227,000 X SpGr)	GMS/HR Multiply by 3.785	Divide by (60 X SpGr)

Step 2: Calculate Liquid Correction Factor from given values

This information is required to size for liquids other than water:
• Specific Gravity of Liquid:____________ @ Operating Conditions
• Liquid Temperature:__________°F @ Operating Conditions
• Liquid Viscosity: _________cps @Operating Conditions
• Specific Gravity of the Float to be used: ___________

Float Specific Gravity				Liquid Density Conversions
Teflon	2.20	316 SS	8.04		From	To Specific Gravity
Glass	2.53	Hastelloy C	8.94		LBS/FT³	Divide by 62.4
Sapphire	3.99	Carboloy	15.00		KG/M³	Divide by 1,000
Titanium	4.50	Tantalum	16.60		API	[141.5 ÷ (131.5+API)]
316L SS	8.03				g/cm³	= SpGr

Liquid Specific Gravity Correction Factor (LSGCF) formula:

3. Determine the Water Equivalent Flow Rate

Water Equivalent Flow Rate = Customer’s Liquid Flow Rate ÷ LSGCF Water Equivalent Flow Rate = ______________________

4. Calculate the maximum or minimum flow rate for the customer’s conditions. (Customer Liquid Flow Rate Scale)

Customer Liquid Flow Rate Scale = Catalog Flow Rate ÷ LSGCF @ 70° F
Customer Liquid Flow Rate Scale = ____________________

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