instructions

1. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 1/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
SUMMARY
1. PURPOSE............................................................................................................................. 1
2. FIELD OF APPLICATION...................................................................................................... 1
3. PRINCIPLE............................................................................................................................ 1
Reminder:..................................................................................................................................... 2
4. SAFETY................................................................................................................................. 2
5. EQUIPMENT ......................................................................................................................... 2
Equipment recommendations............................................................................................. 2
6. WORKING INSTRUCTIONS ................................................................................................. 3
6.1. Evaluation of the number of measurement points........................................................... 3
Circular pipe ................................................................................................................... 3
Rectangular pipe ............................................................................................................ 5
6.2. Measurement of air flow with the Anemometer............................................................... 8
6.3. Calculation of air flow rate .............................................................................................10
1. PURPOSE
Measure the air flow from the outside of air duct inlet.
2. FIELD OF APPLICATION
All LAFARGE Gypsum Division production sites.
3. PRINCIPLE
Determine the average gas velocity at the inlet of a pipe section using the Anemometer with
large measurement device. To measure relevant figures, the section of the pipe or air duct
should have an uniform velocity repartition and should not present any vortex zone or return
flow.
Example of measuring point
(inlet of diluted phase
pneumatic transport)

2. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 2/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
Reminder:
- Do not use the Anemometer in a corrosive and dusty environment.
4. SAFETY
For the measurement of air flow, the technician in charge of the test must wear safety gloves.
5. EQUIPMENT
Equipment recommendations
Equipment Supplier Price estimation
Macro measuring sensor
(Diam.: 80mm)
SCHILTNECHT (Distributor: MESUREUR
France)
1300 Euros

3. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 3/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
MiniAir 2 Display SCHILTNECHT (Distributor: MESUREUR
France)
900 Euros
6. WORKING INSTRUCTIONS
6.1. Evaluation of the number of measurement points
Circular pipe
The method to follow is the “Log-Tchebycheff method” :
• “n” is the number of measurement points per radius (total number of points = 2n)
• “i” appoints one measurement point (1 ≤ i ≤ 2n)
diameter 'D
1st
radius
2nd
radius
i
1 Y1
2n
Yi
Y2n
There is n measurement points per radius and thus 2n measurement points per diameter. Those
points are symmetric to each other from the center of the pipe. There’s no measurement on the
center of the pipe.
“Yi” is calculated as per the equation : Yi = Ci x D using the table presented here under.
Due to the symmetry from the center of the pipe : Ci+ C2n+1-i = 1
n 1
st
radius 2
nd
radius
3
C1 = 0.0320
C2 = 0.1375
C3 = 0.3125
C6 = 0.9680
C5 = 0.8625
C4 = 0.6875
4
C1 = 0.0240
C2 = 0.1000
C3 = 0.1940
C4 = 0.3345
C1 = 0.9760
C2 = 0.9000
C3 = 0.8060
C4 = 0.6655

4. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 4/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
5
C1 = 0.0240
C2 = 0.1000
C3 = 0.1940
C4 = 0.3345
C4 = 0.3565
C1 = 0.0240
C2 = 0.1000
C3 = 0.1940
C4 = 0.3345
C4 = 0.6435
Example : n= 3 with a 300 mm pipe.
In that case the total measurement points is 6 (Y1 to Y6). The hereunder table
presents the calculation results :
1
st
radius 2
nd
radius
i Ci Yi (mm) i Ci Yi (mm)
1 C1 = 0.0320 10 6 C6 = 0.9680 290
2 C2 = 0.1375 41 5 C5 = 0.8625 259
3 C3 = 0.3125 94 4 C4 = 0.6875 206
D = 300 mm
Y1 = 10
Y2 = 41
Y3 = 94
Y4 = 206
Y5 = 259
Y6=290
1 2 3 4 5 6

5. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 5/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
Rectangular pipe
The equal areas are represented on the drawing here under :
L/2n
l/2n
l
n points
N
p
o
i
n
t
s
L
• “N” is the number of measurement points on the length “L”.
• “n” is the number of measurement points on the width “l”.
The number of equal areas is : N x n
The smaller distance from one measuring point to the wall is
n
2
L
for the length.
The smaller distance from one measuring point to the wall is
n
2
l
for the width.
The following tables are presenting some examples for the values of : N, n,
n
2
L
,
n
2
l
.
For different square pipes : 1
l
L
= and for different rectangular pipes : 1
l
L

6. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 6/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
For a square area 1
l
L
=
L (m) N L/2n (cm) l (m) n l/2n (cm)
0.5 2 12.5 0.5 2 12.5
1.0 4 12.5 1.0 4 12.5
1.5 5 15.0 1.5 5 15.0
2.0 6 16.7 2.0 6 16.7
2.5 7 17.9 2.5 7 17.9
3.0 8 18.8 3.0 8 18.8
For a rectangular area 5
.
1
l
L
=
L (m) N L/2n (cm) l (m) n l/2n (cm)
0.75 3 12.5 0.5 2 12.5
1.50 5 15.0 1.0 4 12.5
2.25 7 16.1 1.5 5 15.0
3.00 8 18.8 2.0 6 16.7
3.75 8 23.4 2.5 7 17.9
The curve here under is a resume of those results :
Number of measuring points
as a function of L and l
0
1
2
3
4
5
6
7
8
9
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
L or l (m)
N
or
n

7. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 7/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
Example : Rectangular pipe
length L = 50 cm
width l = 40 cm
Considering the curve here above :
For the length : N = 2
For the width : n = 2
The distances between each point are presented in the table here under :
L (m) 0.5
L (m) 0.4
N 2
n 2
L/2N (mm) 125
l/2n (mm) 100
The drawing for the measurement points location is the following one :
500
400
100
125
The total measurement points is : N x n = 4 x 4 = 16

8. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 8/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
6.2. Measurement of air flow with the Anemometer
• Make sure that the arrow is in the correct
direction of the air flow.
• Measure the air flow rate.
• Record the value from the display

9. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 9/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
• Move the anemometer on the section pipe
according to the defined location of
measurement points.

10. Lafarge Process Kit
Methods
Version 1
Direction Industrielle
Direction Assistance des
Procédés
MEASUREMENT OF AIR FLOW
RATE FROM THE OUTSIDE OF
AIR DUCT INLET
Page : 10/10
Date : March 17, 2006
© Copyright 2006, Lafarge Plâtres
All rights reserved. No part of this document may be reproduced, stored in a retrieval system, translated, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording, or otherwise, without prior written permission of Lafarge Plâtres. CONFIDENTIAL The information contained herein is confidential and proprietary to
Lafarge Plâtres. It may not be disclosed or transferred, directly or indirectly, to any third party without the explicit written permission of Lafarge Plâtres
6.3. Calculation of air flow rate
To calculate the value of the air flow, use Thermicalc software as shown below:
Key in the “yellow cells” the following figures:
- Air flow rate (following the above test method)
- Static pressure (following the method from the Lafarge Process Kit)
- Dry temperature (following the method from the Lafarge Process Kit)
- Wet Bulb temperature (following the method from the Lafarge Process Kit)
- Diameter of the section
- Atmospheric pressure (according to the location of the plant)