B
C
230
*
15 M BARS @ 150 mm O.C.
*
STORM
A
SIZE
*
A
B
4-15 M BARS @ 50 mm O.C.
C
PLAN
A DIMENSION
B
SANITARY SIZE
DIME-
250
300
375
450
NSION
750
780
825
870
915
1675
825
825
870
915
960
1750
900
870
915
960
1000
1830
975
915
960
1000
1045
1905
1050
960
1000
1045
1090
1980
1200
1045
1090
1135
1180
2135
1350
1135
1180
1225
1270
2285
1500
1225
1270
1315
1360
2440
1650
1315
1360
1400
1445
2590
1800
1400
1445
1490
1535
2745
1950
1490
1535
1580
1625
2895
2100
1580
1625
1670
1715
3050
SLAB REINFORCING
SCHEDULE
CHIMNEY WALLS TO BE 230 mm THICK
THROUGHOUT CHAMBER WHERE TOTAL
DEPTH IS LESS THAN 4.6 m & 300 mm
WHERE TOTAL DEPTH IS GREATER
230
230
660
15 mm PARGING
ADJUSTMENT UNITS. IF BRICKS
ARE USED, THICKNESS TO
230
AGREE WITH THICKNESS OF
660
230
230 660 230
CHIMNEY WALLS.
460
660
230
230
23
0
KEYWAY & EXTENDED STEEL
OR 15 M DOWELS @ 300 mm IF
CONCRETE CHIMNEY IS USED.
900
SANITARY
‘
H’
STORM
300
NOTE
915
MIN.
SECTION
*
NOTES:
B
230 mm UNDER 4.6 m
300 mm OVER4.6 m
150
B
*
SECTION
A
A
150
B
*
230
STORM
230
230
150
1200
1200
SEE NOTE 7
SANITARY
‘
H’
300
230
SEE
NOTE
SEE
15 M DOWEL @
460 mm O.C. 75 mm
COVER. LAP 24 DIA.
TO EXTEND 175 mm
INTO BASE
SLAB.
150
900
230
760
760
SEE NOTE 7
15 M BARS @ 460 m m O.
C.VERT.
15 M BARS @ 230 m m O.
C.HORI
Z.
I
N ALL W ALLS
THAN 4.6 m
MAXIMUM 300 mm OF VERTICAL
*
SECTION
C
* PIPE BARREL THICKNESS
+ 230 mm UNDER 4.6 m
+ 300 mm OVER 4.6 m
1. CONCRETE TO BE 32 MPa AT 28 DAYS CAST IN PLACE.
7.
FOR USE ON STRAIGHT RUNS ONLY
2. REINFORCING STEEL TO BE 350 MPa DEFORMED BARS
1.2 m FOR DEPTHS 2.0 m to 2.3 m
MINIMUM COVER TO BE 50 mm LAP 24 BAR DIA.
3. FIRST STEP TO BE 75 to 300 mm BELOW FRAME.
LAST STEP TO BE 300 mm ABOVE BENCHING OR
H=
1.5 m FOR DEPTHS 2.3 m to 2.8 m
STACK 760 mm X 760 mm
1.8 m FOR DEPTHS 2.8 m to 3.2 m
2.1 m FOR DEPTHS 3.2 m and over
STACK 760 mm X 900 mm
600mm ABOVE INVERT IF NO BENCHING.
4. ALL BOXES FOR FUTURE SEWER TO HAVE 50 mm x 100 mm
KEYWAY ON ALL SIDES.
8. PARGING SHALL BE 1:3 MORTAR MIX.
9. WATERPROOFING OVER PARGING TO BE TWO HEAVY COATS
5. TOP OF BENCHING TO BE SLOPED TO A MAXIMUM OF 8:1
6. IF DEPTH IS SUFFICIENT TO WARRANT A SAFETY PLATFORM
CHIMNEY SHALL BE 1200 mm x 1200 mm.
OF BITUMEN.
10. WHERE PIPES JOIN AT MAINTENANCE HOLE, JOINTS ARE
TO BE WATERTIGHT WITH THE APPROVED SEAL.
All dimensions are in millimetres unless otherwise shown.
ENGINEERING AND CONSTRUCTION SERVICES STANDARD DRAWING
REV 1
APR 2013
TYPICAL DUAL MAINTENANCE HOLE
T-701.013-1
WITH INVERTS LEVEL
MINIMUM STORM SIZE 750 mm DIAMETER
NTS
SHEET 1