SAUDI ARABIAN STANDARD
SASO …./2006
1.8
INTRODUCTION TO THE CONSTRUCTION SCHEDULES
1.8.1
Rectangular Table Reading Guide
RECTANGULAR
DUCT
1.
Determine pressure class assigned by the designer.
2.
Go to the reinforcement schedule for the duct pressure class. Table 1-4 is used in this review.
3.
The greater duct dimension determines the gage for all sides. Reinforcement may be different on sides with unequal dimension.
4.
The duct side will either qualify for flat type joint connections because the duct wall gage is thick enough to control reflection without needing reinforcement or will require an alphabet letter code reinforcement that is suited for the width, the wall thickness and a maximum spacing interval. a)
The gage of duct not require reinforcement is in column 2. See Figure 1-7.
b)
Duct reinforcement options are in columns 3 to 10: Read horizontally right from the greater duct dimension in column 1 and vertically under a reinforcement interval spacing (in columns 3 to 10) of your choice. The number in the cell is minimum duct gage; the letter code is type of joint or intermediate reinforcement, whichever you choose. This applies for joint-to-joint, joint-to-intermediate, or intermediate-to-intermediate intervals. If, for example, you are using 5' (1.5 m) joint spacing and do not want to use between-joint reinforcements stay in the 5' (1.5 m) column (column 6) until it becomes "Not Designed"; then you go to column 9 to find the joint rating and the intermediate (between-joint) bracing and the potentially lighter gage duct wall permitted with 2-1/2' (0.75 m) reinforcement spacing.
5.
Having found the gage for the wide side, check column 2 to see if that gage is exempt from reinforcement on the short side. If it is not, find which column (of 3 to 10) this gage in; there find the maximum spacing in the column heading and the prescribed joint (or reinforcement) size (letter code) listed in the gage. If the maximum short side reinforcement spacing thus found exceeds a joint spacing that you are committed to, go to the column with the joint spacing to find the joint size. Even though the duct gage listed at this width-spacing cell may be less, the joint rating cannot be less than at this cell.
6.
Beading and crossbreaking are not substitutes for reinforcement. These are not required for any of the following conditions: liner or external insulation is used; width is less than 19"; duct pressure class is over 3" w.g.; duct gage is over 20 (1.0 mm); unbraced panel area is 10 square feet (0.93 square meters) or less. Otherwise, one or the other must be used.
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