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Legend: Explanations & Illustrations Rationale Note Revision history Print

ANNEX 3B - LIMITS OF UNPROTECTED OPENINGS

B1.0 CALCULATION OF PERMITTED LIMITS OF UNPROTECTED AREAS

B1.1 The permitted limit of unprotected areas in any side of a building or compartment shall be calculated by reference to the requirements of B2.0.

B1.2 For the purposes of this Annex, the expression "unprotected area" has the meaning ascribed to it by Cl.1.4.108, but in calculating the size of unprotected areas or the permitted limit of unprotected areas, the following provisions shall apply -

a. where any area of an external wall is an unprotected area, only because it has combustible material attached to it as cladding, the area of that unprotected area shall be deemed to be half the area of such cladding;

b. when unprotected openings in the same compartment are recessed at a distance or an angle to the plane of reference, the width of the unprotected opening can be reduced accordingly when projected to the plane of reference based on Table III and IV. However, such reduction is not applicable to the following:

(1) Concave building profile or the like where a specific point on the receiving panel receives radiation from more than one source. 

(2) When the unprotected opening is along a continuous circular profile where its size and angle cannot be determined.

c. no account shall be taken of any of the following:

(1) an unprotected area which does not exceed 0.1m2 and which is not less than 1.5m from any other unprotected area in the same side of the building or compartment (unless that other falls within (3) below);

(2) one or more unprotected areas having an area (or, if more than one, the aggregate area) not exceeding 1m2 and not less than 4m from any other unprotected area in the same side of the building or compartment (except any such area as is specified in (1) above);

(3) an unprotected area in any part of an external wall which forms part of a protected shaft;

(4) an unprotected area in the side of a building not divided into compartments, if the area is not less than 28m above any ground adjoining that side of the building.

B2.0 Rules of calculation by reference to an enclosing rectangle

B2.1 The conditions of this Part of this Annex shall be satisfied if a building or compartment is so situated that no point on the relevant boundary is either between the relevant plane of reference and the side of the building or compartment or at a distance from the relevant plane of reference which is less than the distance specified in the Tables to this Part of this Annex, according to the purpose group of the building or compartment, the dimensions of the enclosing rectangle and the unprotected percentage.

B2.2 For the purpose of this Part of this Annex:

a. “relevant boundary” means as defined in Cl.1.4.87 and for the purpose of this calculation is either parallel to the side of the building under consideration or at an angle of not more than 80° with that side;

b. “plane of reference” means any vertical plane which touches the side or some part of the side of a building or compartment but which (however far extended) does not pass within the structure of such building or compartment (and for this purpose, any balcony, coping or similar projection shall be deemed not to be part either of that side or of the structure); and the relevant plane of reference shall in each case be taken as that most favourable in that respect to the person erecting the building;

c. “enclosing rectangle” means the smallest rectangle on the relevant plane of reference which would:

(1) enclose all the outer edge of any unprotected area of the building or, if the building is divided into compartments, of the compartment (other than any of an unprotected area which is at an angle of more than 80° to the plane of reference the outer edges being for this purpose projected on the plane of reference by line perpendicular to such plane;

(2) have two horizontal sides; and

(3) have height and width falling within those listed in the Tables to this Part of this Annex.

d. “unprotected percentage” means the percentage of the area of the enclosing rectangle which is equal to the aggregate of the unprotected areas taken into account in calculating the enclosing rectangle and as projected on it.

 TABLE 1 - BUILDINGS OR COMPARTMENTS OF PG I, PG II, PG III, PG IV, PG VII & PG VIII (for Open-sided Car Parking Decks only)
Enclosing RectangleDistance (in metres) from Relevant Boundary for Unprotected Percentage not exceeding
Ht.Width20%30%40%50%60%70%80%90%100%
3 metres3m1.01.01.01.51.51.52.02.02.0
6m1.01.01.52.02.02.02.52.53.0
9m1.01.01.52.02.52.53.03.03.5
12m1.01.52.02.02.53.03.03.53.5
15m1.01.52.02.52.53.03.53.54.0
18m1.01.52.02.52.53.03.54.04.0
21m1.01.52.02.53.03.03.54.04.5
24m1.01.52.02.53.03.53.54.04.5
27m1.01.52.02.53.03.54.04.04.5
30m1.01.52.02.53.03.54.04.04.5
40m1.01.52.02.53.03.54.04.05.0
No limit1.01.52.02.53.03.54.04.05.0
6 metres3m1.01.01.52.02.02.02.52.53.0
6m1.01.52.02.53.03.03.54.04.0
9m1.02.02.53.03.54.04.54.55.0
12m1.52.53.03.54.04.55.05.05.5
15m1.52.53.04.04.55.05.55.56.0
18m1.52.53.54.04.55.05.56.06.5
21m1.52.53.54.05.05.56.06.57.0
24m1.52.53.54.55.05.56.07.07.0
27m1.52.53.54.55.06.06.57.07.5
30m1.52.53.54.55.06.06.57.08.0
40m1.52.53.54.55.56.57.08.08.5
50m1.52.53.54.55.56.57.58.09.0
60m1.52.53.55.05.56.57.58.59.5
80m1.52.53.55.06.07.07.58.59.5
100m1.52.53.55.06.07.08.08.510.0
No limit1.52.53.55.06.07.08.08.510.0
9 metres3m1.01.01.52.02.52.53.03.03.5
6m1.02.02.53.03.54.04.54.55.0
9m1.52.53.54.04.55.05.55.56.0
12m1.53.03.54.55.05.56.06.57.0
15m2.03.04.05.05.56.06.57.07.5
18m2.03.54.55.06.06.57.08.08.5
21m2.03.54.55.56.57.07.58.59.0
24m2.03.55.05.56.57.58.09.09.5
27m2.03.55.06.07.07.58.59.510.0
30m2.03.55.06.07.08.09.09.510.5
40m2.03.55.56.57.58.59.510.511.5
50m2.04.05.56.58.09.010.011.512.5
60m2.04.05.57.08.09.511.011.513.0
80m2.04.05.57.08.510.011.512.513.5
100m2.04.05.57.08.510.011.512.514.5
120m2.04.05.57.08.510.011.512.514.5
No limit2.04.05.57.08.510.512.012.515.0
12 metres3m1.01.52.02.02.53.03.03.53.5
6m1.52.53.03.54.04.55.05.05.5
9m1.53.03.54.55.05.56.06.57.0
12m1.53.54.55.06.06.57.07.58.0
15m2.03.55.05.56.57.08.08.59.0
18m2.54.05.06.07.07.58.59.010.0
21m2.54.05.56.57.58.59.010.010.5
24m2.54.56.07.08.08.59.510.511.5
27m2.54.56.07.08.09.010.511.012.0
30m2.54.56.57.58.59.510.511.512.5
40m2.55.06.58.09.510.512.012.014.0
50m2.55.07.08.510.011.013.014.015.0
60m2.55.07.09.010.512.013.514.516.0
80m2.55.07.09.011.013.014.516.017.0
100m2.55.07.59.511.513.515.016.518.0
120m2.55.07.59.511.513.515.017.018.5
No limit2.55.07.59.512.014.015.517.019.0
15 metres3m1.01.52.02.52.53.03.53.54.0
6m1.52.53.04.04.55.05.55.56.0
9m2.03.04.05.05.56.06.57.07.5
12m2.03.55.05.56.57.08.08.59.0
15m2.04.05.56.57.08.09.09.510.0
18m2.54.56.07.08.08.59.510.511.0
21m2.55.06.57.58.59.510.511.012.0
24m3.05.06.58.09.010.011.012.013.0
27m3.05.57.08.59.510.511.512.513.5
30m3.05.57.58.510.011.012.013.514.0
40m3.06.08.09.511.012.513.515.016.0
50m3.56.08.510.012.013.515.016.517.5
60m3.56.58.510.512.514.015.517.018.0
80m3.56.59.011.013.515.017.018.520.0
100m3.56.59.011.514.016.018.019.521.5
120m3.56.59.011.514.016.518.520.522.5
No limit3.56.59.012.014.517.019.021.023.0
18 metres3m1.01.52.02.52.53.03.54.04.0
6m1.52.53.54.04.55.05.56.06.5
9m2.03.54.55.06.06.57.08.08.5
12m2.54.05.06.07.07.58.59.010.0
15m2.54.56.07.08.08.59.510.511.0
18m2.55.06.57.58.59.511.011.513.0
21m3.05.57.08.09.510.511.512.513.0
24m3.05.57.58.510.011.012.013.014.0
27m3.56.08.09.010.511.512.513.514.5
30m3.56.58.09.511.012.013.514.515.5
40m4.07.09.011.012.013.515.016.517.5
50m4.07.09.511.513.015.016.518.019.0
60m4.07.510.012.014.016.017.519.520.5
80m4.07.510.013.015.017.019.021.022.5
100m4.07.510.013.516.018.020.522.524.0
120m4.07.510.014.016.519.021.023.525.5
No limit4.08.010.014.017.019.522.024.026.5
21 metres3m0.51.52.02.53.03.03.54.04.5
6m1.52.53.54.05.05.56.06.57.0
9m2.03.54.55.56.57.07.58.59.0
12m2.54.05.56.57.58.59.010.010.5
15m2.55.06.57.58.59.510.511.012.0
18m3.05.57.08.09.510.511.512.513.0
21m3.06.07.59.010.511.012.513.514.0
24m3.56.08.09.510.512.013.014.015.0
27m3.56.58.510.011.513.014.015.016.0
30m4.07.09.010.512.013.014.516.016.5
40m4.57.510.012.013.515.016.518.019.0
50m4.58.011.013.014.516.518.020.021.0
60m4.58.511.513.515.517.519.521.022.5
80m4.58.512.014.517.019.021.023.525.0
100m4.59.012.015.518.020.522.525.027.0
120m4.59.012.016.018.521.523.526.528.5
No limit4.59.012.016.019.022.025.026.529.5
24 metres3m0.51.52.02.53.03.53.54.04.5
6m1.52.53.54.55.05.56.07.07.0
9m2.03.55.05.56.57.58.09.09.5
12m2.54.56.07.08.08.59.510.511.5
15m3.05.06.58.09.010.011.012.013.0
18m3.05.57.58.510.011.012.013.014.0
21m3.56.08.09.510.512.013.014.015.0
24m3.56.58.510.011.512.514.015.016.0
27m4.07.09.011.012.513.515.016.017.0
30m4.07.59.511.513.014.015.517.018.0
40m4.58.511.013.014.516.018.019.020.5
50m5.09.012.014.016.017.519.521.022.5
60m5.09.512.515.017.019.021.023.024.5
80m5.010.013.516.518.521.023.525.527.5
100m5.010.013.517.020.022.525.027.529.5
120m5.510.013.517.520.523.526.529.031.0
No limit5.510.013.518.021.024.027.530.032.5
27 metres3m1.01.52.02.53.03.54.04.04.5
6m1.52.53.54.55.06.06.57.07.5
9m2.03.55.06.07.07.58.59.510.0
12m2.54.56.07.08.09.010.511.012.0
15m3.05.57.08.59.510.511.512.513.5
18m3.56.08.09.010.511.512.513.514.5
21m3.56.58.510.011.513.014.015.016.0
24m3.57.09.011.012.513.515.016.017.0
27m4.07.510.011.513.014.016.017.018.0
30m4.08.010.012.013.515.017.018.019.0
40m5.09.011.514.015.517.519.020.522.0
50m5.59.512.515.017.019.021.022.524.0
60m5.510.513.516.018.520.522.524.526.5
80m6.011.014.517.520.522.525.027.529.5
100m6.011.015.519.021.524.527.030.032.0
120m6.011.515.519.522.526.028.532.034.0
No limit6.011.515.520.023.527.029.533.035.0
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TABLE 2 - BUILDINGS OR COMPARTMENTS OF PG V, PG VI, & PG VIII (see Table 1 for Open-sided Car Parking Decks)
Enclosing RectangleDistance (in metres) from Relevant Boundary for Unprotected Percentage not exceeding
Ht.Width20%30%40%50%60%70%80%90%100%
3 metres3m1.01.52.02.02.52.52.53.03.0
6m1.52.02.53.03.03.53.54.04.0
9m1.52.53.03.54.04.04.55.05.0
12m2.02.53.03.54.04.55.05.55.5
15m2.02.53.54.04.55.05.56.06.0
18m2.02.53.54.05.05.06.06.56.5
21m2.03.03.54.55.05.56.06.57.0
24m2.03.03.54.55.05.56.07.07.5
27m2.03.04.04.55.56.06.57.07.5
30m2.03.04.04.55.56.06.57.58.0
40m2.03.04.05.05.56.57.08.08.5
50m2.03.04.05.06.06.57.58.09.0
60m2.03.04.05.06.07.07.58.59.5
80m2.03.04.05.06.07.08.09.09.5
No limit2.03.04.05.06.07.08.09.010.0
6 metres3m1.52.02.53.03.03.53.54.04.0
6m2.03.03.54.04.55.05.55.56.0
9m2.53.54.55.05.56.06.57.07.0
12m3.04.05.05.56.57.07.58.08.5
15m3.04.55.56.07.07.58.09.09.0
18m3.54.55.56.57.58.09.09.510.0
21m3.55.06.07.08.09.09.510.010.5
24m3.55.06.07.08.59.510.010.511.0
27m3.55.06.57.58.59.510.511.012.0
30m3.55.06.58.09.010.011.012.012.5
40m3.55.57.08.510.011.012.013.014.0
50m3.55.57.59.010.511.513.014.015.0
60m3.55.57.59.511.012.013.515.016.0
80m3.56.07.59.511.513.014.516.017.5
100m3.56.08.010.012.013.515.016.518.0
120m3.56.08.010.012.014.015.517.019.0
No limit3.56.08.010.012.014.016.018.019.0
9 metres3m1.52.53.03.54.04.04.55.05.0
6m2.53.54.55.05.56.06.57.07.0
9m3.54.55.56.06.57.58.08.59.0
12m3.55.06.07.07.58.59.09.510.5
15m4.05.56.57.58.59.510.011.011.5
18m4.56.07.08.59.510.011.012.012.5
21m4.56.57.59.010.011.012.013.013.5
24m5.06.58.09.511.012.013.013.514.5
27m5.07.08.510.011.512.513.514.515.0
30m5.07.09.010.512.013.014.015.016.0
40m5.57.59.511.513.014.515.517.017.5
50m5.58.010.012.514.015.517.018.519.5
60m5.58.011.013.015.016.518.019.521.0
80m5.58.511.513.516.017.519.521.523.0
100m5.58.511.514.516.518.521.022.524.5
120m5.58.511.514.517.019.521.523.526.0
No limit5.58.511.515.017.520.022.524.527.0
12 metres3m2.02.53.03.54.04.55.05.55.5
6m3.04.05.05.56.57.07.58.08.5
9m3.55.06.07.07.58.59.09.510.5
12m4.56.07.08.09.09.511.011.512.0
15m5.06.58.09.010.011.012.013.013.5
18m5.07.08.510.011.012.013.014.014.5
21m5.57.59.010.512.013.014.015.016.0
24m6.08.09.511.512.514.015.016.016.5
27m6.08.010.512.013.514.516.017.017.5
30m6.58.510.512.514.015.016.517.518.5
40m6.59.512.014.015.517.518.520.021.0
50m7.010.013.015.017.019.020.523.023.0
60m7.010.513.516.018.020.021.523.525.0
80m7.011.014.517.019.521.523.526.027.5
100m7.511.515.018.021.023.025.528.030.0
120m7.511.515.018.522.024.027.029.531.5
No limit7.512.015.519.022.525.028.030.534.0
15 metres3m2.02.53.54.04.55.05.56.06.0
6m3.04.55.56.07.07.58.09.09.0
9m4.05.56.57.58.59.510.011.011.5
12m5.06.58.09.010.011.012.013.013.5
15m5.57.09.010.011.512.513.514.515.0
18m6.08.09.511.012.513.514.515.516.5
21m6.58.510.512.013.514.516.016.517.5
24m6.59.011.013.014.515.517.018.019.0
27m7.09.511.513.515.016.518.019.020.0
30m7.510.012.014.016.017.018.520.021.0
40m8.011.013.516.018.019.521.022.523.5
50m8.512.015.017.519.521.523.025.026.0
60m8.512.515.518.021.023.525.027.028.0
80m9.013.517.020.023.025.528.030.031.5
100m9.014.018.021.524.527.530.032.534.5
120m9.014.018.522.525.528.531.534.537.0
No limit9.014.519.023.027.030.034.036.039.0
18 metres3m2.02.53.54.05.05.06.06.56.5
6m3.54.55.56.57.58.09.09.510.0
9m4.56.07.08.59.510.011.012.012.5
12m5.07.08.510.011.012.013.014.014.5
15m6.08.09.511.012.513.514.515.516.5
18m6.58.511.012.013.514.516.017.018.0
21m7.09.511.513.014.516.017.018.019.5
24m7.510.012.014.015.516.518.519.520.5
27m8.010.512.514.516.517.519.520.521.5
30m8.011.013.515.517.018.520.521.522.5
40m9.012.015.017.519.521.523.525.026.0
50m9.513.016.519.021.523.526.027.529.0
60m10.014.017.520.523.026.027.529.531.0
80m10.015.019.022.526.028.531.033.535.0
100m10.016.020.524.028.031.033.536.038.5
120m10.016.521.025.529.532.535.539.041.5
No limit10.017.022.026.530.534.037.041.043.5
21 metres3m2.03.03.54.55.05.56.06.57.0
6m3.55.06.07.08.09.09.510.010.5
9m4.56.57.59.010.011.012.013.013.5
12m5.57.59.010.512.013.014.015.016.0
15m6.58.510.512.013.514.516.016.517.5
18m7.09.511.513.014.516.017.018.019.5
21m7.510.012.514.015.517.018.520.021.0
24m8.010.513.015.016.018.020.021.022.0
27m8.511.514.016.018.019.021.022.523.5
30m9.012.014.516.518.520.522.023.525.0
40m10.013.516.519.021.523.025.527.028.5
50m11.014.518.021.023.525.528.030.031.5
60m11.515.519.522.525.528.030.532.533.5
80m12.017.021.025.028.531.534.036.538.5
100m12.018.022.527.031.034.537.040.042.0
120m12.018.523.528.532.536.539.543.045.5
No limit12.019.025.029.534.538.041.545.548.0
24 metres3m2.03.03.54.55.05.56.07.07.5
6m3.55.06.07.08.59.510.010.511.0
9m5.06.58.09.511.012.013.013.514.5
12m6.08.09.511.512.514.015.016.016.5
15m6.59.011.013.014.515.517.018.019.0
18m7.510.012.014.015.516.518.519.520.5
21m8.010.513.015.016.518.020.021.022.0
24m8.511.514.016.018.019.521.022.524.0
27m9.012.515.017.019.020.521.524.025.5
30m9.513.015.518.020.021.523.525.026.5
40m11.014.518.020.523.025.027.529.030.5
50m12.016.019.522.525.527.530.032.033.5
60m12.517.021.024.527.530.032.535.036.5
80m13.518.523.527.531.034.537.039.541.5
100m13.520.025.029.533.537.040.043.045.5
120m13.520.526.531.036.039.543.046.549.0
No limit13.521.027.532.537.542.045.549.552.0
27 metres3m2.03.04.04.55.56.06.57.07.5
6m3.55.06.57.58.59.510.511.012.0
9m5.07.08.510.011.512.513.514.515.0
12m6.08.010.512.013.514.516.017.017.5
15m7.09.511.513.515.016.518.019.020.0
18m8.010.512.514.516.517.519.520.521.5
21m8.511.514.016.018.019.021.022.523.5
24m9.012.515.017.019.020.522.524.025.5
27m10.013.016.018.020.022.024.025.527.0
30m10.013.517.019.021.023.025.026.528.0
40m11.515.519.022.024.526.529.030.532.5
50m12.517.021.024.027.029.532.034.536.0
60m13.518.522.526.529.532.035.037.039.0
80m14.520.525.029.533.036.539.542.044.0
100m15.521.527.032.036.540.543.046.548.5
120m15.522.528.534.039.043.046.550.553.0
No limit15.523.529.535.040.544.548.552.055.5

 

TABLE 3

Percentage of the Width of the Unprotected Openings upon their Projection onto the Plane of Reference (in view of distance of the openings from the plane of reference)

 

DISTANCE TO REFERENCE PLANE

1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 11m 12m 13m 14m 15m 16m 17m 18m 19m 20m 21m 22m 23m 24m 25m 26m 27m
Width of Unprotected Opening* 3m 72% 54% 41% 33% 28% 24% 21% 18% 16% 15% 13% 12% 11% 11% 10% 9% 9% 8% 8% 7% 7% 7% 6% 6% 6% 6% 6%
6m 85% 72% 62% 54% 47% 41% 37% 33% 30% 28% 25% 24% 22% 21% 19% 18% 17% 16% 15% 15% 14% 13% 13% 12% 12% 11% 11%
9m 90% 80% 72% 65% 59% 54% 49% 45% 41% 38% 36% 33% 31% 29% 28% 26% 25% 24% 22% 21% 21% 20% 19% 18% 17% 17% 16%
15m 94% 88% 82% 77% 72% 68% 64% 60% 57% 54% 51% 48% 46% 43% 41% 40% 38% 36% 35% 33% 32% 31% 30% 29% 28% 27% 26%
21m 95% 91% 87% 83% 79% 75% 72% 69% 66% 63% 61% 58% 56% 54% 51% 50% 48% 46% 44% 43% 41% 40% 39% 38% 36% 35% 34%
27m 96% 93% 90% 86% 83% 80% 77% 75% 72% 70% 67% 65% 63% 61% 59% 57% 55% 54% 52% 50% 49% 48% 46% 45% 44% 43% 41%
30m 97% 94% 90% 88% 85% 82% 79% 77% 74% 72% 70% 68% 66% 64% 62% 60% 58% 57% 55% 54% 52% 51% 49% 48% 47% 46% 45%
40m 98% 95% 93% 90% 88% 86% 84% 82% 80% 78% 76% 74% 73% 71% 69% 68% 66% 65% 63% 62% 60% 59% 58% 57% 55% 54% 53%
50m 98% 96% 94% 92% 90% 89% 87% 85% 84% 82% 80% 79% 77% 76% 74% 73% 72% 70% 69% 68% 66% 65% 64% 63% 62% 61% 60%
60m 98% 97% 95% 94% 92% 90% 89% 88% 86% 85% 83% 82% 81% 79% 78% 77% 76% 74% 73% 72% 71% 70% 69% 68% 67% 66% 65%
70m 99% 97% 96% 94% 93% 92% 90% 89% 88% 87% 86% 84% 83% 82% 81% 80% 79% 78% 76% 75% 74% 73% 72% 71% 70% 70% 69%
80m 99% 98% 96% 95% 94% 93% 92% 90% 89% 88% 87% 86% 85% 84% 83% 82% 81% 80% 79% 78% 77% 76% 75% 74% 74% 73% 72%
90m 99% 98% 97% 96% 95% 94% 93% 92% 90% 90% 89% 88% 87% 86% 85% 84% 83% 82% 81% 80% 79% 78% 78% 77% 76% 75% 74%
100m 99% 98% 97% 96% 95% 94% 93% 92% 91% 90% 90% 89% 88% 87% 86% 85% 84% 84% 83% 82% 81% 80% 80% 79% 78% 77% 77%
110m 99% 98% 97% 96% 96% 95% 94% 93% 92% 91% 90% 90% 89% 88% 87% 87% 86% 85% 84% 83% 83% 82% 81% 81% 80% 79% 78%
120m 99% 98% 98% 97% 96% 95% 94% 94% 93% 92% 91% 90% 90% 89% 88% 88% 87% 86% 85% 85% 84% 83% 83% 82% 81% 81% 80%
 
 
 
 
 
 
 
 

Table3-1

Table3-2

Illustration A (Enlarged)

TABLE 3 - (cont'd)

Percentage of the Width of the Unprotected Openings upon their Projection onto the Plane of Reference (in view of distance of the openings from the plane of reference)

 

DISTANCE TO REFERENCE PLANE

28m 29m 30m 31m 32m 33m 34m 35m 36m 37m 38m 39m 40m 41m 42m 43m 44m 45m 46m 47m 48m 49m 50m 51m 52m 53m 54m
Width of Unprotected Opening* 3m 5% 5% 5% 5% 5% 5% 4% 4% 4% 4% 4% 4% 4% 4% 4% 3% 3% 3% 3% 3% 3% 3% 3% 3% 3% 3% 3%
6m 11% 10% 10% 10% 9% 9% 9% 9% 8% 8% 8% 8% 7% 7% 7% 7% 7% 7% 6% 6% 6% 6% 6% 6% 6% 6% 6%
9m 16% 15% 15% 14% 14% 13% 13% 13% 12% 12% 12% 11% 11% 11% 11% 10% 10% 10% 10% 9% 9% 9% 9% 9% 9% 8% 8%
15m 25% 24% 24% 23% 22% 22% 21% 21% 20% 19% 19% 19% 18% 18% 17% 17% 17% 16% 16% 16% 15% 15% 15% 14% 14% 14% 14%
21m 33% 32% 32% 31% 30% 29% 28% 28% 27% 26% 26% 25% 25% 24% 24% 23% 23% 22% 22% 21% 21% 21% 20% 20% 19% 19% 19%
27m 40% 39% 38% 37% 37% 36% 35% 34% 33% 33% 32% 31% 31% 30% 29% 29% 28% 28% 27% 27% 26% 26% 25% 25% 24% 24% 24%
30m 43% 42% 41% 40% 40% 39% 38% 37% 36% 35% 35% 34% 33% 33% 32% 31% 31% 30% 30% 29% 29% 28% 28% 27% 27% 26% 26%
40m 52% 51% 50% 49% 48% 47% 46% 45% 45% 44% 43% 42% 41% 41% 40% 39% 39% 38% 37% 37% 36% 36% 35% 35% 34% 34% 33%
50m 59% 58% 57% 56% 55% 54% 53% 52% 51% 50% 50% 49% 48% 47% 47% 46% 45% 45% 44% 43% 43% 42% 41% 41% 40% 40% 39%
60m 64% 63% 62% 61% 60% 59% 58% 57% 57% 56% 55% 54% 54% 53% 52% 51% 51% 50% 49% 49% 48% 47% 47% 46% 46% 45% 45%
70m 68% 67% 66% 65% 64% 63% 63% 62% 61% 60% 59% 59% 58% 57% 57% 56% 55% 55% 54% 53% 53% 52% 51% 51% 50% 50% 49%
80m 71% 70% 69% 68% 68% 67% 66% 65% 65% 64% 63% 63% 62% 61% 60% 60% 59% 58% 58% 57% 57% 56% 55% 55% 54% 54% 53%
90m 74% 73% 72% 71% 71% 70% 69% 68% 68% 67% 66% 66% 65% 64% 64% 63% 62% 62% 61% 61% 60% 59% 59% 58% 58% 57% 57%
100m 76% 75% 74% 74% 73% 72% 72% 71% 70% 70% 69% 68% 68% 67% 66% 66% 65% 65% 64% 63% 63% 62% 62% 61% 61% 60% 60%
110m 78% 77% 76% 76% 75% 74% 74% 73% 72% 72% 71% 71% 70% 69% 69% 68% 68% 67% 67% 66% 65% 65% 64% 64% 63% 63% 62%
120m 79% 79% 78% 77% 77% 76% 76% 75% 74% 74% 73% 73% 72% 72% 71% 70% 70% 69% 69% 68% 68% 67% 67% 66% 66% 65% 65%
 
 
 
 
 
 
 
 
 

Table3-3

Table3-4

Illustration A (Enlarged)

 

TABLE  4

Percentage of the Width of the Unprotected Openings upon their Projection onto the Plane of Reference (in view of distance of the openings from the plane of reference)

Angle of unprotected opening to reference plane*

10°

15°

20°

25°

30°

35°

40°

45°

50°

55°

60°

65°

70°

75°

80°

85°

90°

Actual percentage of unprotected opening width on reference plane

96%

91%

87%

83%

78%

74%

70%

66%

62%

58%

54%

50%

46%

43%

39%

36%

32%

29%

Table4 Diagram