Thumb Rules-VENTILATION & CEILING FAN

 

Recommended values for air changes  (NBC-5.2.2.1) & CPWD
Application	Air Change per Hour
Assembly rooms	4 to 8
Bakeries	20 to 30
Banks/building societies	4 to 8
Bathrooms	6 to 10
Bedrooms	2 to 4
Billiard rooms	6 to 8
Cafes and coffee bars	10 to 12
Canteens	8 to 12
Cellars	3 to 10
Changing rooms	6 to 10
Churches	1 to 3
Cinemas and theatres	10 to 15
Club rooms 12, Min	12 to 15
Compressor rooms	10 to 12
Conference rooms	8 to 12
Corridors	5 to 10
Dairies	8 to 12
Dance halls	12
Dye works	20 to 30
Electroplating shops	10 to 12
Entrance halls	3 to 5
Factories and work shops	8 to 10
Foundries	15 to 30
Garages	6 to 8
Glass houses	25 to 60
Gymnasium	6
Hair dressing saloon	10 to 15
Hospitals sterilizing	15 to 20
Hospital wards	6 to 8
Hospital domestic	15 to 20
Laboratories	6 to 15
Launderettes	10 to 15
Laundries	10 to 30
Lavatories	6 to 15
Lecture theatres	5 to 8
Libraries	3 to 5
Lift cars	20
Living rooms	3 to 6
Mushroom houses	6 to 10
Offices	6 to 10
Paint shops (not cellulose)	10 to 20
Photo and X-ray dark room	10 to 15
Public house bars	12
Recording control rooms	15 to 25
Recording studios	10 to 12
Restaurants	8 to 12
Schoolrooms	5 to 7
Shops and supermarkets	8 to 15
Shower baths	15 to 20
Stores and warehouses	3 to 6
STP rooms	30
Squash courts	4
Swimming baths	10 to 15
Toilets	6 to 10
Underground vehicle parking	6
Utility rooms	15 to 30
Welding shops	15 to 30
Note: The ventilation rates may be increased by 50 % where heavy smoking occurs or if the room is below the ground.

 

Recommended values for air changes
Application	Air Change per Minute
Assembly Hall	7
Auditorium	10
Barber Shop	6
Basement	8
Battery Room	4
Boiler Room	1
Bowling Alley	5
Engine Room	6
Gymnasium	8
Projection Booth	2
Church	15
Factory	6
Laundry	2
Summer Cooling	1
Classroom	6
Forge Room	3
Locker Room	3
Toilet	3
Dance Hall	5
Foundry	4
Machine Shop	8
Transformer Room	1
Department Store	6
Garage	5
Plating Room	3
Warehouse	12
Dry Cleaning	5
General Office	10
Pressing Room	1
Welding Shop	2

 

TYPE A CEILING FANS (IS-374)
FAN SIZE	AIR DELIVERY (m3/min)	MAXIMUM INPUT
900	140	42
1050	165	48
1200	215	50
1400	270	60
1500	300	63

 

Size of Ceiling Fan
Area	Suggested Fan Size
Up to 9 Square Meters	900mm (36″)
Up to 12 Square Meters	1067mm (42″)
Up to 18 Square Meters	1200mm (48″)
Up to 30 Square Meters	1300mm (52″)
Up to 40 Square Meters	1400mm (56″)

 

Size and Number of Ceiling Fans for Rooms (As per NBC Table-10)
Room Width	Room Length
	Fan Size (mm) /No of Fan
	4 Meter	5 Meter	6 Meter	7 Meter	8 Meter	9 Meter	10 Meter	11 Meter	12 Meter	14 Meter	16 Meter
3 Meter	1200/1	1400/1	1500/1	1050/2	1200/2	1400/2	1400/2	1400/2	1200/3	1400/3	1400/3
4 Meter	1200/1	1400/1	1200/2	1200/2	1200/2	1400/2	1400/2	1500/2	1200/3	1400/3	1500/3
5 Meter	1400/1	1400/1	1400/2	1400/2	1400/2	1400/2	1400/2	1500/2	1400/3	1400/3	1500/3
6 Meter	1200/2	1400/2	900/4	1050/4	1200/4	1400/4	1400/4	1500/4	1200/6	1400/6	1500/6
7 Meter	1200/2	1400/2	1050/4	1050/4	1200/4	1400/4	1400/4	1500/4	1200/6	1400/6	1500/6
8 Meter	1200/2	1400/2	1200/4	1200/4	1200/4	1400/4	1400/4	1500/4	1200/6	1400/6	1500/6
9 Meter	1400/2	1400/2	1400/4	1400/4	1400/4	1400/4	1400/4	1500/4	1400/6	1400/6	1500/6
10 Meter	1400/2	1400/2	1400/4	1400/4	1400/4	1400/4	1400/4	1500/4	1400/6	1400/6	1500/6
11 Meter	1500/2	1500/2	1500/4	1500/4	1500/4	1500/4	1500/4	1500/4	1500/6	1500/6	1500/6
12 Meter	1200/3	1400/3	1200/6	1200/6	1200/6	1400/6	1400/6	1500/6	1200/7	1400/9	1400/9
13 Meter	1400/3	1400/3	1200/6	1200/6	1200/6	1400/6	1400/6	1500/6	1400/9	1400/9	1500/9
14 Meter	1400/3	1400/3	1400/6	1400/6	1400/6	1400/6	1400/6	1500/6	1400/9	1400/9	1500/9

 

Ceiling Fan Criteria (As per NBC)
Capacity of a ceiling fan	=55D m3/min ,D= the longer dimension of a room
Height of fan blades above the floor	= (3H + W)/4, where H is the height of the room, W is the height of work plane.
Minimum distance between fan blades and the ceiling	=0.3 m.

 

Size Your Fan for the Room (ENERGY STAR)
Room Size	Fan Size
Up to 75 sq. ft.	29 To 36 inches or smaller
75 to 144 sq. ft.	36 to 42 inches
144 to 225 sq. ft.	44 to 50 inches
225 to 400 sq. ft.	50 to 54 inches
Over 400 Sq. ft	54 To 72 inches multiple fans installed

 

Minimum Efficacy Levels of Ceiling Fans (ENERGY STAR )
Airflow (CFM)	Minimum Efficacy Level (CFM/W)
Low	At low speed, airflow of 1250 CFM and an efficiency of 155 cfm/W.
Medium	At medium speed, airflow of 3000 CFM and an efficiency of 100 cfm/W.
High	At high speed, airflow of 5000 CFM and an efficiency of 75 cfm/W.

 

Ceiling Fan Rod Extend Length
Ceiling Height	Pole Length
8 Feet	No Down rod
9 Feet	6 Inches
10 Feet	12 Inches
11 Feet	18 Inches
12 Feet	24 Inches
13 Feet	36 Inches
14 Feet	48 Inches
15 Feet	60 Inches
20 Feet or greater	72 Inches

 

Ceiling Fan Height Chart
Ceiling Height	Distance
< 8 Feet	Choose a low-profile ceiling fan. 18″ Minimum distance blade to wall. 7′ minimum distance blade to floor.
> 9 Feet	Choose a ceiling fan down rod. 18″ Minimum distance blade to wall.

 

Distance between Two Fans
Fan Size	Distance
36″ (900mm)	1.8 Meter
42″ (1000mm)	2 Meter
48″ (1200mm)	2.5 Meter
56″ (1400mm)	3 Meter

 

Fan Blade Pitch Angle and No of Blade
Fan Blade pitch	It is the angle of fan’s blades (measured in degrees) and it is in conjunction with the fan motor,
	It is show how well fan is able to circulate air.
	Higher blade pitches typically move more air in cubic feet per minute, or CFM.
	The optimal blade pitch for a ceiling fan is between 12 and 15 degrees.
Blade number	It can contribute to the amount of air movement as well.
	The typical ceiling fan comes standard with 4 or 5 blades.
	Fans with more blades are usually quieter but also move less air.

 

Ceiling Fan Size Guide
Room Size	Room Type	Blade Span	CFM Rating
Up to 100 Sq. Ft	Bathroom, Breakfast Nooks, Utility Rooms, Small Bedrooms, Porches	29” To 36″           (700 to 900mm)
100 To 144 Sq. Ft	Bathroom, Breakfast Nooks, Utility Rooms, Small Bedrooms, Porches	36” To 42″        (700 to 1000mm)	1,000 To 3,000
100 To 225 Sq. Ft	Medium Bedrooms, Kitchens, Dining Rooms, Dens, Patios	44” To 50″         (1200 to 1270mm)	1,600 To 4,500
225 To 400 Sq. Ft	Master Bedrooms, Family Rooms, TV Rooms, Small Garages, Gazebos	Over 50” (1270mm)	2,300 To 6,500
Over 400 Sq. Ft	Great Rooms, Large Garages, Basements, and Open Floor Plans	Over 62” (1600mm)	5,500 To 13,500

 

Ceiling Fan Size
Room Size	Fan Blade Sweep
< 90 Sq.Foot	15″ to 42″ (400 to 1000mm)
90 to 100 Sq.Foot	44″ to 46″ (1000 to 1200mm)
100 to 150 Sq.Foot	52″ to 54″ (1300 to 1400mm)
> 150 Sq.Foot	56″ to 70″ (1400 to 1800mm)

 

Ceiling Fan Speed and RPM
Speed	Watt	RPM	Air Flow (M3/Hr)	Efficiency (M3/Hr/Watt)
Low	62.3	171	8736	140
Medium	34.9	130	6774	197
High	15.2	86	4066	267

 

Various distance of Ceiling Fan in Room
Ceiling Fan Blades and Floor	7 ft
Ceiling Fan Blades and Ceiling	8 to 10 inches
Ceiling Fan Blades and Light fixtures.	39 inches
Ceiling Fan Blades and Wall	18 inches

 

Minimum Efficacy Levels of Ceiling Fans (ENERGY STAR )
Speed	Air Flow	Efficiency (CFM/Watt)
At low speed	1250 CFM	155 cfm/W
At medium speed	3000 CFM	100 cfm/W
At high speed	5000 CFM	75 cfm/W

 

Size of Rod / Cord for Hanging Light (As per NBC)
Nominal Cross-Sectional Area of Twin Cord mm for Hanging Light	Maximum Permissible Weight mm2  kg
0.5	2
0.75	3
1	5
1.5	5.3
2.5	8.8
4	14

 

Standard Exhaust Fan Size
Fan DIA (MM / inches)	Speed (RPM)	Input Power	Phase	Current (A)	M3/HR   (CFH)	M3/MI   (CFM)	Sound level dB
150/6″	1200	24	Single	0.1	270	5	44 To 50
200/8″	1350	28	Single	0.12	500	8	44 To 50
250/10″	1350	36	Single	0.15	800	13	44 To 50
305/12″	1400	50	Single	0.4	1710	29	50 To 55
305/12″	900	50	Single	0.21	1145	19	35 To 40
380/15″	1400	160	Single	0.75	3250	54	60 To 65
380/15″	1400	150	Three	0.45	3250	54	60 To 65
380/15″	900	90	Single	0.4	2000	33	50 To 55
380/15″	900	100	Three	0.29	2000	33	50 To 55
457/18″	1400	410	Single	1.7	6120	102	65 To 70
457/18″	1400	410	Three	0.65	6120	102	65 To 70
457/18″	900	150	Single	0.65	3900	65	55 To 60
457/18″	900	150	Three	0.3	3900	65	55 To 60
610/24″	700	240	Single	0.4	7100	118	55 To 60
610/24″	900	500	Three	0.5	7100	118	55 To 60
610/24″	900	500	Single	2.6	9400	157	60 To 65
610/24″	900	500	Three	0.85	9400	157	60 To 65
750/30″	900	870	Single	3.8	12000	200	70 To 75
750/30″	900	910	Three	1.8	12000	200	70 To 75
900/36″	700	1200	Three	2.4	28100	468	75 To 80