1.
CLIMATE
Mahoney’s Table
Presented by-
Ar.Abhinav Srivastav
Assistant Professor
B.Arch, M.A.R.D, M.Tech IIT-R

2.
Mahoney’s Table
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• When the climatic pattern emerging from the data clearly corresponds to warm
humid or hot-dry climate types, it is relatively easy to arrive performance
specifications
• A weighting system must be used to assess the relative importance of
conflicting requirements.
• The system must take into account the duration and severity of the various
climatic factors.
•
• Based on such a system, a series of tables have been derived by “C Mahoney”.
• Table1- to record the most essential climatic data
• Table2- facilities a diagnosis of the climate
• Table3- translates into performance specifications or sketch design
recommendations.

3.
Table-1 (first part)
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
Location Baghdad, Iraq
Longitude 44° 24´ E.
Latitude 33° 20´ N.
Altitude 34 m
• Choose the Location and then according the location find Longitude,
Latitude and Altitude.

4.
Table-1 (first part)
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• From metrological records enter the monthly mean maximum and mean minimum air
temperature values in the first two line. All values should be rounded to the 0.5°C
• Find the mean range for each month by deducting the mean minimum from the mean
maximum value and enter these in third line.
• In the separate box on the right enter the highest of the twelve maxima and the lowest of
the twelve minima respectively.
• By adding these two values and dividing it by two find the annual mean temperature
and enter this value in the box marked AMT.
• By finding the difference between these two values get the annual mean range and enter
it in the box marked AMR.
Air temperature : °C
J F M A M J J A S O N D High AMT
Monthly mean max. 16 18.5 22 29 36 41 43.5 43.5 40 34 24.5 17.5 43.5 23.5
Monthly mean min. 4 5.5 9 14.5 20 23.5 25.5 24.5 21 16 10.5 5 4 39.5
Monthly mean range 12 13 13 14 16 17.5 18 18 19 18 14 12.5 Low AMR

5.
Table-1 (second part)
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
Monthly mean max. a.m. 87 78 74 68 46 34 32 32 38 50 67 89
Monthly mean min. p.m. 50 41 35 27 18 13 12 13 15 21 39 51
Average 68.5 59.5 54.5 47.5 32 23.5 22 23.5 26.5 35.5 53 70
Humidity group 3 3 3 2 2 1 1 1 1 2 3 3
Humidity group:
1 If average RH: below 30 %
2 30-50 %
3 50-70%
4 Above 70 %
• From metrological records enter the monthly mean maxima and minima of relative
humidity in the first two lines.
• Find the average humidity for each month by adding the above two values and dividing
it by two values and dividing it by two. Enter these average in third line
• Establish the humidity group for each month according to the following categories.

6.
Table-1 (second part)
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
Rainfall, mm 24 25 28 15 7 0 0 0 0 3 22 26 150 Total
Wind, prevailing NW. NW. NW. NW. NW. NW. NW. NW. NW. NW. NW. NW.
Wind, secondary SE. SE. N N N N N & W N N N N SE
J F M A M J J A S O N D
Rain and Wind
• In the last two lines enter the prevailing and secondary wind direction for each month, on
the basis of first and second peak in published wind frequency tables or figures
• Enter the monthly average rainfall value in the fifth line. Adding these twelve values find
the annual total rainfall and enter this in the separate box at the end of the line.

7.
Table-2 (first part)
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
AMT
over 20 °C
AMT
15-20 °C
AMT
below 15 °C
Comfort limits Day Night Day Night Day Night
Humidity groups
1 26-34 17-25 23-32 14-23 21-30 12-21
2 25-31 17-24 22-30 14-22 20-27 12-20
3 23-29 17-23 21-28 14-21 19-26 12-19
4 22-27 17-21 20-25 14-20 18-24 12-18
• Table represents to relation between comfort limit (in term of temperature) and the
humidity group

8.
Table-2 (first part)
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• Enter the first and fourth lines the monthly mean minimum and maximum temperature
• Find the upper and lower comfort limits for the day and night of each month, on the basis of
the above table, as defined by the annual mean temperature and the humidity group for each
month. Enter these values in 2, 3, 5 and 6 respectively
• Compare the day comfort limit with the mean maxima and the night comfort limit with the
mean minima and establish the nature of thermal stress by entering the following symbols in
last two lines: H (hot) -if mean is above limit
O (comfort) –if mean is within limits
C (cold) –if mean is below the limit
J F M A M J J A S O N D
Monthly mean max. 16 18.5 22 29 36 41 43.5 43.5 40 34 24.5 17.5 23.5AMT
Day comfort: upper 29 29 29 31 31 34 34 34 34 31 29 29
lower 23 23 23 25 25 26 26 26 26 25 23 23
Monthly mean min. 4 5.5 9 14.5 20 23.5 25.5 24.5 21 16 10.5 5
Night comfort: upper 23 23 23 24 24 25 25 25 25 24 23 23
lower 17 17 17 17 17 17 17 17 17 17 17 17
Thermal stress: day C C C O H H H H H H O C
night C C C C O O H O O C C C

9.
Table-2 (second part)
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• Certain group of symptoms (nature of thermal stress, some climate characteristic and the
duration of both) indicate the remedial action the designer could take. The method developed
uses six indicators (three humid indicator H 1, 2, 3 and three arid indicator A 1, 2, 3)
Applicable when:
Meaning: Indicator
Thermal
stress Rainfall
Humidity
Group
Monthly mean range
Day Night
Air movement essential H1 H 4
H 2,3 Less than 10
Air movement desirable H2 O 4
Rain protection necessary H3 Over
200 mm
Thermal capacity necessary A1 1,2,3 More than 10
Out-door sleeping desirable A2 H 1,2
H O 1,2 More than 10
Protection from cold A3 C

10.
Table-2 (second part)
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• The process to be followed is to check thermal stress indices (day and night) the humidity
group, the rainfall and the monthly mean range of temperature against the definition of the
indicators and place a tick in the line of the appropriate indicator where the month’s data
corresponds to the definition.
Humid: H1 0
H2 0 Total
H3 0
Arid: A1             12
A2      5
A3     4
J F M A M J J A S O N D

11.
Table-3 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• Building should be oriented on east-west axis, the long elevations facing north and south, to
reduce expose the sun.
• Building should be planned around small courtyard if thermal storage is required of the most
of the year, i.e when the hot dry season is dominant.
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Layout
0-10 1 Orientation north and south
(long axis east-west)11,12 5-12
0-4  2 Compact courtyard planning

12.
Table-3 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• Building should be broadly spaced for breeze penetration.
• If wind penetration is needed only for the part of the year, provision must be made for
protection from cold or dusty hot winds
• Compact planning is recommended if the air movement requirement is insignificant.
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Spacing
11,12 3 Open spacing for breeze
penetration
2-10 4 As 3, but protection form hot
and cold wind
0,1 5 Compact lay-out of estates

13.
Table-3 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• Rooms should be single baked with windows in the north and south walls, to ensure air
movement by ample cross ventilation.
• If air movement is never essential, and is desirable for not more than a month, rooms can be
double banked and there is not much need for cross ventilation.
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Air movement
3-12 6 Rooms single banked, permanent
provision for air movement1,2 0-5
6-12

7 Double banked rooms, temporary
provision for air movement
0
2-12
0,1 8 No air movement requirement

14.
Table-3 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• Large, between 40 and 80% of the north and south walls. These need not be fully glazed, but
should be protected from the sun, sky glare and rain, preferably by horizontal overhangs
• Very small, less than 20%of the wall.
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Openings
0,1 0 9 Large openings, 40-80%
11,12 0,1  10 Very small openings, 10-20%
Any other
conditions
11 Medium openings, 20-40%

15.
Table-3 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• External wall should be light with low thermal capacity.
• Internal wall should also be light where hot dry condition prevail for a short time only
• Internal walls should be heavy and massive, where any occurrence of hot and dry conditions
is combined with a large annual mean range of temperature (over 20 degree C)
• Both external internal wall should be massive
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Walls
0-2 12 Light walls, short time-lag
3-12  13 Heavy external and internal
walls

16.
Table-3 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• A light but well insulated roof, with low thermal capacity
• A heavy roof, with substantial thermal capacity, giving a time lag of at least 8 hours.
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Roofs
0-5 14 Light, insulated roofs
6-12  15 Heavy roofs, over 8 h time-lag

17.
Table-3 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• Special protective measures are needed if rain is frequent and heavy- such as deep
verandahs, wide overhang and covered passage.
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Rain protection
3-12 17 Protection from heavy rain
necessary
Out-door sleeping
2-12  16 Space for out-door sleeping
required
• It should be provided on roof, balconies or in patios, so that sleepers are exposed to the
coldest part of the night sky in increase heat loss by outgoing radiation.

18.
Table-4 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Size of opening
0-1 0 1 Large 40%-80%
1-12
2 Medium 25%-40%
2-5
6-10 3 Small 15%-25%
11-12
0-3 4 Very Small 10%-20%
4-12

5 Medium 25%-40%

19.
Table-4 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Protection of Openings
0-2 8 Exclude direct sunlight
2-12 9 Provide Protection from rain
Rain protection
3-12
6
In north and south walls at
body height on windward size
1-2
0-5
6-12
7
As above, opening also in
internal walls0 2-12

20.
Table-4 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
Walls and Floor
0-2 10 Light low thermal capacity
3-12  11 Heavy over 8h time lag
Roofs
10-12
0-2 12 Light, reflective surface,
Cavity
3-12
13 Light, well insulated
0-9
0-5
6-12  14 Heavy over8h time lag

21.
Table-4 Specifications
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
Indicator Totals from Table 2
H1 H2 H3 A1 A2 A3
0 0 0 12 5 4
External features
1-12

15 Space for outdoor sleeping
1-12 16 Adequate rain water drainage

22.
References
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
• Manual Housing of Tropical Climate

23.
Climate-Mahoney’s Table
Presented by-Ar.Abhinav Srivastav
Thanks
Ar. Abhinav Srivastav
Assistant Professor
B.Arch, M.A.R.D, M.Tech (IIT-R)
Mobile No.- +91 945 638 3485
+91 735 538 5658
Email id- abhinav.sunny@rediffmail.com