designing auxiliary ventilation

7/29/2019 designing Auxiliary Ventilation

1/12

SCHAUENBURG

VENTILATION

Designing a Mine AuxiliaryVentilation System


2/12

Auxiliary Ventilation

Purpose

Auxiliary ventilation is designed to provide adequate ventilation to a dead-endentry or tunnel, to remove or dilute hazardous gasses or dust, and to provide

sufficient and clean air for individuals and equipment to work efficiently.

Considerations:

Air velocity in the entry or tunnel

Air quantity for diesel equipment

Air quantity for peopleAir quantity to dilute or remove gasses and dust

Air quantity for cooling or other needs

Head room over haulage or material transport equipment

Length of duct

Handling and hanging problems

Potential for damage from blasting and other activities

Duct and fans must be sized to ensure that the fans

are not working in a stall (i.e., the fan is attempting to

move more air than the duct will allow)

A larger duct allows for a more efficient and lower

horsepower system

Legal and contract requirements for fans and duct

Preferred direction of airflow - suction or blowing

Most leakage occurs at the joints and longer lengths have

significantly less leakage

Quantityof air required

Physicalconstraints

Otherconsiderations

SCHAUENBURGVENTILATION


3/12

Flexible forced duct friction loss chart

(Layflat duct)

StaticPressure(ins.

watergaugeper100duct)

DuctDiam

eter

1,000 cfm 2,000 cfm 5,000 cfm 10,000 cfm 20,000 cfm 50,000 cfm 100,000 cfm 200,000 cfm

.47m3/sec. .94 m3/sec. 2.36m3/sec 4.72m3/sec. 9.44 m3/sec. 2.36 m3/sec. 47.2m3/sec. 94.4m3/sec.

Air Quantity

.02

.03

.04

8200

mm

1025

0mm

1230

0mm

1435

0mm

1640

0mm

1845

0mm

20

500m

m

246

00mm

3076

0mm

3690

0mm

421,0

50mm

481

,200mm

601

,500m

m

721

,800mm

842

,100m

m

962

,400m

m

10.002.5kPa

8.00

6.00

1.00.25kPa

.80

.60

.500.13kPa

.40

.30

.20

.10

.025kPa

5.001.25kPa

4.00

3.00

2.00

.08

.06

.050.013kPa


4/12

Flexible suction duct friction loss chart

(Spiral duct)

.02

.03

.04

10.002.5kPa

8.00

6.00

1.00.25kPa

.80

.60

.500.13kPa

.40

.30

.20

.10

.025kPa

5.001.25kPa

4.00

3.00

2.00

.08

.06

.050.013kPa

StaticPressure(ins.watergaugeper100du

ct)

DuctDiamet

er



Air Quantity

123

00mm

143

50mm

164

00mm

184

50mm

205

00mm

246

00mm

307

60mm

369

00mm

399

75mm

481

,200m

m

541

,350m

m

601

,500m

m

721

,800m

m

902

,250m

m

962

,400m

m


820

0mm

102

50mm

22

550

mm

348

50mm

421

,050m

m

661

,650m

m

781

,800m

m

842

,100m

m

286

50mm


5/12

Evaluate the Different Types of Duct

Lowest initial-cost suction duct

Required on some projects Non-flammable

Holds high positive and negative pressureMedium leakage Low friction

Best suited for:

Moderate length ventilation runs (less than 3,000 ft.)

Drill and shoot operations

Single use applications

Most durable suction duct Flame resistant

Holds up well to abuse Light-weight

Holds high positive and negative pressure

Low friction factor

Best suited for:

Short-length ventilation runs (less than 1,500 ft.)

Multiple reuse operations

Drill and shoot operations

Mine development

Flame resistant Can expand and contract length

Weight dependent on negative pressure rating

Can be stored in small area

Best suited for:

Starter tunnels

Short ventilation runs

Flexible connections in other type of duct

Low cost Flame resistant Low leakage in long lengths

Pressure rating dependent on material, construction

Requires additional fan for reversing air flow on OSHA jobs

Medium friction factor Many grades availableRequires special expertise in applications for booster fans

Best suited for:

Short ventilation runs using low cost duct

Long ventilation runs using high-quality long-length ducts

TBM tunnels

Steel

Fiberglass

Flexible

Suction

Lay flat


6/12

Calculating Losses

Dynamic Losses

The pressure loss in each fitting, inlet and outlet must be calculated separately and isbased on the velocity pressure of air at that point in the system.

Velocity pressure Pv =

Friction Losses

Friction loss curves, which are provided in this brochure, are designed to give the

pressure loss due to friction in the duct. The curves are based on the following formula:

For all equations, the definitions are:

H = pressure loss in in. w.g. A = area of duct in square feet

C = loss coefficient K = the friction factor for the

V = air velocity in feet/minute material

L = length in feet (Fiberglass duct is 11.7;

O = perimeter in feet Steel duct is 12;

Q = air quantity in 100,000 cfm Cassette duct is 15;

(60,000 cfm would be .60) Lay flat duct is 18;

= air density (.075 for standard air) in lb/ft3 Flexible suction duct is 27)



7/12

Fiberglass duct friction loss chart

StaticPressure(in

s.watergaugeper100

duct)

DuctDiame

ter



Air Quantity

123

00mm

143

50mm

164

00mm

184

50mm

205

00mm

225

50mm

246

00mm

287

00mm

307

60mm

348

50mm

369

00mm

421

,050m

m

481

,200m

m

541

,350m

m

601

,500m

m

721

,800m

m

842

,100m

m

.02

.03

.04

10.002.5kPa

8.00

6.00

1.00.25kPa

.80

.60

.500.13kPa

.40

.30

.20

.10

.025kPa

5.001.25kPa

4.00

3.00

2.00

.08

.06

.050.013kPa


8/12

Steel duct friction loss chart

StaticPressure(ins.

watergaugeper100duct)

DuctDiameter



Air Quantity

.02

.03

.04

8200

mm

1025

0mm

1230

0mm

1435

0mm

1640

0mm

1845

0mm

20

500m

m

2460

0mm

3076

0mm

3690

0mm

421,0

50mm

481

,200m

m

601

,500m

m

721

,800m

m

842

,100m

m

962,4

00mm

10.002.5kPa

8.00

6.00

1.00.25kPa

.80

.60

.500.13kPa

.40

.30

.20

.10

.025kPa

5.001.25kPa

4.00

3.00

2.00

.08

.06

.050.013kPa

22

550m

m

28

650m

m

3480

0mm

39975m

m

541

,350m

m

661

,650m

m

781

,950m

m

902

,250m

m



9/12


10/12

Reading fan and headloss curves

How to use the friction curves

To determine the friction loss, find theaverage air quantity in the duct (air at

heading + 1/2 leakage), follow the line up

to your duct diameter and read across to

determine the static pressure drop per 100 feet.

Multiply this number by the length of duct

(also in hundreds of feet) to obtain the

friction losses.

For an oval duct, use the hydraulic

diameter formula to calculate the equivalent

round diameter:DH =

For example:

An application requires 28,000 cfm at

the heading. We have 2,000 feet of 36 flexible

forced duct and 4,000 cfm of leakage. The

average air quantity in the duct is 30,000 cfm.

This gives us .8 in. w.g./100 feet or 16 total.

How to use the fan curve

Read across at the total pressure, then

up from the quantity to determine if the

intersection point falls on or under the

fan curve.

To obtain the total pressure

requirement for the fan, add the friction

losses, dynamic losses and one velocity

pressure to obtain the total pressure inthe system.

In the above example, if we also have

8 of dynamic losses and 1.25 velocity

pressure, we would have a total pressure

loss of 25.25 and a fan quantity of 32,000 cfm.

Therefore, by using a fan chart we can see

that a 2 x 100 HP 33 fan will meet the

requirements.

1,000 cfm 5,000 cfm 10,000 cfm 30,000 cfm

.47m3/sec. 2.36m3/sec 4.72m3/sec.

Air Quantity

.02

.03

.04

1.00.25kPa

.80

.60

.500.13kPa

.40

.30

.20

.10

.025kPa

.08

.06

.050.013kPa

4A

O

2-STAGE CONTRA ROTATING FAN

246

00mm

307

60mm

369

00mm

421

,050

481,20

0

601

,500m



11/12

General Reference

Velocity Pressures

Conversion Factors

Air densityat different

altitudes andtemperatures

VEL. VP VEL. VP VEL. VPFPM In. Water FPM In.Water FPM In.Water

500 .016 1800 .202 4400 1.21

600 .022 2000 .249 4600 1.32

700 .031 2200 .302 4800 1.44

800 .040 2400 .359 5000 1.56

900 .050 2600 .421 5200 1.69

1000 .062 2800 .489 5400 1.82

1100 .075 3000 .561 5600 1.96

1200 .090 3200 .638 5800 2.10

1300 .105 3400 .721 6000 2.24

1400 .122 3600 .808 6200 2.40

1500 .140 3800 .900 6400 2.55

1600 .160 4000 .998 6600 2.72

1700 .180 4200 1.10 6800 2.88

-1000 31.02 0.0936 0.0886 0.0858 0.0824 0.0792 0.0762 0.0735

0 29.92 0.0903 0.0854 0.0827 0.0794 0.0764 0.0735 0.0709

1000 28.86 0.0871 0.824 0.0798 0.0766 0.0736 0.0709 0.684

2000 27.82 0.0839 0.0794 0.0769 0.0738 0.0710 0.0684 0.0660

3000 26.81 0.0808 0.0765 0.0741 0.0712 0.0684 0.0659 0.0635

4000 25.84 0.0779 0.0738 0.0715 0.0686 0.0660 0.0635 0.0612

5000 24.89 0.0751 0.0710 0.0688 0.0661 0.0635 0.0611 0.0590

6000 23.98 0.0723 0.0684 0.0663 0.0636 0.0612 0.0589 0.0569

7000 23.09 0.0697 0.0659 0.0639 0.0613 0.0589 0.0546 0.0526

8000 22.22 0.0671 0.0634 0.0614 0.0590 0.0567 0.0546 0.0526

9000 21.38 0.0644 0.0610 0.0591 0.0568 0.0546 0.0525 0.0506

10000 20.58 0.0620 0.0587 0.0569 0.0546 0.0525 0.0495 0.0488

Altitude Atmospheric

Pressure

Temperature in degrees Fahrenheit

-20 0 20 40 60 80 100

QUANTITY STANDARD STANDARD STANDARD OTHER UNITSUNITS ENGLISH UNITS METRIC (SI) UNITS

in. wg pascals psiinwg 1 248.36 .03602

pascals .00403 1 .00015psi 27.761 6894.7 1

inHg 13.635 3386.4 .49116mm WG .03937 9.7779 .00142mm Hg .53681 133.32 .01934

Bar 407.98 101325 14.696

ft/min m/s m/minFt/min 1 .00508 .30480

M/s 196.85 1 60.000M/min 3.2808 .01667 1

Kph .05468 .00028 .01667Mph 88.000 .44704 26.822Knots 101.34 .51479 30.887

PRESSURE

VELOCITY

cfm m3/s m3/minCfm 1 .000472 .02832

M3/s 2118.9 1 60.000M3/min 35.314 .01667 1

VOLUMEFLOW


12/12

2233 Sanford DriveGrand Junction, Colorado 81505 USA

Tel: 970-245-9400Fax: 970-245-9402

E-mail: [email protected] page: www.schauenburg-us.com

Schauenburg Ventilation Products

FLEXIBLE

Lay flat, spiral, forced, exhaust, shaft, cassettes and all fittings

FIBERGLASS

Round, oval, forced, exhaust, fittings, and accessories

STEEL

18 & 20 gauge, corrugated & smooth, fittings, coupling bands

BRATTICE

Plain rolls, curtains, fly pads, pogo sticks, special products

FANS & FAN SILENCERS

Axial flow, permissible, accessories, center pod silencers

DUST COLLECTORS

Schauenburg is known industry-wide for partnering with customers to engineersolutions for ventilation projects. We welcome inquiries for technical assistance and

the opportunity to assist you with new or existing projects.

A HALF CENTURY OF WORLDWIDE ENGINEERING EXPERIENCE GOES INTO

MANUFACTURING A COMPLETE LINE OF INTEGRATED PRODUCTS DESIGNED FOR ALL

TYPES OF VENTILATION PROJECTS. CALL OR FAX FOR INFORMATION.

Members of the Schauenburg Worldwide

Group of Companies

Schauenburg Tunnel Ventalation

Schauenburg Industries, Ltd., Canada

Flexadux Plastics Ltd., Great Britain

Schauenburg Flexadux (PTY.) Ltd., South Africa

designing auxiliary ventilation

Documents