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 (W)
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 (W) 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

 

 

About Jignesh.Parmar
Jignesh Parmar has completed M.Tech (Power System Control), B.E(Electrical). He is member of Institution of Engineers (MIE) and CEng,India. Membership No:M-1473586.He has more than 16 years experience in Transmission -Distribution-Electrical Energy theft detection-Electrical Maintenance-Electrical Projects (Planning-Designing-Technical Review-coordination -Execution). He is Presently associate with one of the leading business group as a Deputy Manager at Ahmedabad,India. He has published numbers of Technical Articles in “Electrical Mirror”, “Electrical India”, “Lighting India”,”Smart Energy”, “Industrial Electrix”(Australian Power Publications) Magazines. He is Freelancer Programmer of Advance Excel and design useful Excel base Electrical Programs as per IS, NEC, IEC,IEEE codes. He is Technical Blogger and Familiar with English, Hindi, Gujarati, French languages. He wants to Share his experience & Knowledge and help technical enthusiasts to find suitable solutions and updating themselves on various Engineering Topics.

9 Responses to Thumb Rules-VENTILATION & CEILING FAN

  1. shishirdutt says:

    Dear Mr. Parmar,
    First of all I wish to thank you for all your great efforts you have been putting all these years to publish so much useful information. This info on fans is of great use to many.
    However there seems to be some issue with the following section – “Ceiling Fan Speed and RPM” under low speed you have placed higher rpm and vice-versa. Pls. confirm.

    Best regards
    Shishir Dutt
    Associate Professor
    Tolani Maritime Institute
    Pune

  2. Dr Mukesh Kumar says:

    Mr Jignesh ji,

    Good Morning!

    I am really thankful to your kind honour for utilizing your notes. I am making a dictionary of your notes for the students I teach sometimes in Marine Academies as visiting faculty. I did my Engineering in 1985 from Indian Naval Ship Valsura [Naval Engineering Institute] – Electrical Base, Jamnagar.

    Regards,
    Dr Mukesh Kumar

  3. ankita says:

    Hi Sir, I would like to get in touch to discuss the blog written by you and an association for long term. Please get in touch with me over email – ankita.l@axis-india.com

  4. VISHNU BABU says:

    THANK YOU SIR

  5. Nishchal Chowdhary says:

    Dear Jigneshji, Good information on Ventilation and Cieling Fan. I have one question on Short Ckt MVA Rating of Substation. How to calculate MVA Short CKT Rating at Input of a Substation which is receiving power form another substation. Please clarify? Thanks! Regards, Nishchal Chowdhay 9406600319

    On Sat, 2 Nov 2019 at 08:02, Electrical Notes & Articles wrote:

    > Jignesh.Parmar posted: ” 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 ” >

  6. Nishchal Chowdhary says:

    Dear Jigneshji,
    Good information on Ventilation and Cieling Fan.
    I have one question on Short Ckt MVA Rating of Substation.
    How to calculate MVA Short CKT Rating at Input of a Substation which is receiving power form another substation.
    Please clarify?
    Thanks!
    Regards,
    Nishchal Chowdhay
    9406600319

  7. heri says:

    tanks, your information

  8. Babu Thomas says:

    Thanks

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