Design calculation sheetProject no: Date: 4/9/2023 Sheet no.: 1 2 Computed by:

Subject: Checked by:

Exhaust hoods Approved by:

Exhaust hoods are essential in kitchens, laboratories and many industrial application for removing

fumes, mists, vapors, aerosols, particulates, hazardous substances, polluting contaminants

In general, for an exhaust hood to be efficient

where

y = distance between table and exhaust hood (m)c = circumference of the hood (m)

(1) can be modified to calculate required air volume

Exhaust Hood Calculator

The air flow volume in the exhaust hood can be calculated below

0.2 capture velocity - v1 - (m/s)

1.2 vertical distance from table to hood - y - (m)

3 circumference exhaust hood - c - (m)

1.728 Air Volume Flow (m3/s)

3661 Air Volume Flow (CFM)

the height - y - should not exceed 1.20 m (4 ft)the distance - x - should not be less than 1/3 y

the capture velocity - v1 - should not be less than 0.15 - 0.20 m/s (30 - 40 ft/min)

Note! Potential hazardous and polluting applications requires special solutions. Always check local regulations.

The capture velocity - v1 - of the exhaust hood can be estimated with the empirical equation

v1 = q / 2 y2 c         (1)

v1 = capture velocity (m/s)q = air volume flow (m3/s)

q = 2 v1 y2 c         (1a)

Exhaust Hood with internal Plate

The efficiency of an exhaust hood can be improved by adding an internal plate.

Exhaust Hood with Side Walls

The exhaust hood efficiency can be further improved by adding side walls.

The required air volume for an exhaust hood with a plate can in general be reduced to approximately 80% compared to an exhaust hood without a plate.

Design calculation sheetProject no: 09-15-1 Date: 4/9/2023 Sheet no.: 1 1 Computed by:

Subject: Checked by:

Approved by:

Smoke Evacuation Fan Pressurisation Fan

30" x 30" 0.0 m3/scapture velocity - v1 - (m/s)0 lps12600 CFM

At 0 fpm : f = 0.00 ''/100 ft.Roof 30" x 30"

10200 CFM Grille Sizing based on 1000 fpm face velocity

Second 30" x 18" 4 grilles => 0 lps/grille6800 CFM 0 cfm/grille

P.D = 0.0 '' = 0 PaFirst 22"x18"

3400 CFM Fan Selected : Woods

Model :……………..Ground

SR 750x500 380/3/60 ### HP0 lps Typical

of

Data

Page 7

Building Height Fire Pressure Wind Stack Effect Design Pressure

(m) (Pa) (Pa) (Pa)

0 8.5 8 25

5 8.5 8 25

25 8.5 10.5 25

50 8.5 13 50

100 8.5 19.5 50

150 8.5 29.5 50

Size

2 m x 800 mm 5.6 0.01

Single Leaf Doors in Frame Opening Outwards 3 m x 800 mm 5.6 0.02

Double Leaf Doors with or without Central Rebate 2 m x 1.6 m 9.2 0.03

Lift Door 2 m High x 2 m Wide 8.0 0.06

Double Leaf Doors with or without Central Rebate

7.2.3.9 Stair Pressurization.

7.2.3.9.1

Smokeproof enclosures using stair pressurization shall use an approved engineered system with a design

pressure difference across the barrier of not less than 0.05 in. water column (12.5 Pa) in sprinklered

buildings, or 0.10 in. water column (25 Pa) in nonsprinklered buildings, and shall be capable of

maintaining these pressure differences under likely conditions of stack effect or wind. The pressure

difference across doors shall exceed that which allows the door to begin to be opened by a force

of 30 lbf (133 N) in accordance with 7.2.1.4.5.

7.2.1.4.5

The forces required to fully open any door manually in a means of egress shall not exceed 15 lbf (67 N) to release

the latch, 30 lbf (133 N) to set the door in motion, and 15 lbf (67 N) to open the door to the minimum required width.

Opening forces for interior side-hinged or pivoted-swinging doors without closers shall not exceed 5 lbf (22 N).

These forces shall be applied at the latch stile.

Crack Length (m)

Leakage Area (m2)

Single Leaf Doors in Frame Opening into Pressurized Space