(1)
Materials. Pipe, tubing, fittings, and traps to be
used on any part of the sanitary drainage system in a building or adjacent to a
building shall comply with all relevant sections of
248 CMR
3.00 through
10.00.
(2)
Determining Size of Drainage
System.
(a)
Fixture
Units for Drainage Piping. The waste discharge calculations for
the drainage system piping shall be computed in terms of drainage fixture units
in accordance with
248
CMR
10.15:
Table 1:
Fixture Unit Values for Various Plumbing Fixtures and
248
CMR
10.15(2)(b).
(b)
Values for Continuous
Flow. Fixture unit values for continuous or semi-continuous flow
into a building sanitary drainage system, such as from a waste pump, sewage
ejector pump, or similar device that discharges sewage waste shall be computed
on the basis of two fixture units for each gallon per minute of flow.
Exception: Installation of ejector pumps installed in
compliance with 10.15(9): Table 5 with a maximum of 20
GPM.
(3)
Selecting the Size of Drainage Piping. Pipe sizes
shall be determined from
248
CMR
10.15(7):
Table
1,
2 and
3 based on drainage fixture
unit values calculated from
248
CMR
10.15(7):
Table
1:
Fixture Unit Valves for Various Plumbing Fixtures
and 248 CMR
10.15(2)(b).
(4)
Minimum Size of Soil and
Waste Stacks. No soil or waste stack shall be smaller than the
largest horizontal waste branch connected thereto, (
See
248
CMR
10.15(7):
Table
1:
Fixture Unit Values for Various Plumbing Fixtures
and 248 CMR
10.15(7):
Table
3:
Maximum Loads in Fixture Units for Any One Branch Interval
on Multistory Soil and Waste Stacks).
(5)
Provision for the
Installation of Future Fixtures. When future drainage provisions
are considered regarding the potential installation of other fixtures, the
drains provided shall be considered in determining the final required sizes of
drains and vent pipes.
(6)
Size of Underground Drainage Piping.
(a)
Underground or Basement
Floor. No portion of the drainage system installed underground
shall be less than two inches in diameter.
(b)
Sanitary Piping Installed
Through the Foundation Wall.
1.
Sanitary piping that pass through an exterior foundation wall shall be no less
than four inches in diameter,
Exceptions:
a. When serving a Hazardous Waste System
installed in accordance with (248 CMR
10.13).
b. When serving a residential laundry drain
is conducted to a separate (Local Board of Health Authorized) dry-well disposal
system. The minimum size drain shall be two inches in diameter.
c. When serving as a waste for baptistries or
similar type fixtures, the drain shall be a minimum of two inches in diameter.
See
248
CMR
10.10(11).
d. When serving exclusively as the discharge
from a semi-positive displacement grinder pump, and if so, the following shall
be satisfied:
i. The minimum pipe size for a
semi-positive displacement grinder pump discharge shall be HA-inch and shall
provide a self-cleaning velocity of no less than two feet per second.
ii. The velocity in the pipe shall not be
more than seven feet per second.
iii. A full port discharge valve and check
valve shall be provided and made accessible inside the building.
iv. The waste discharge from semi-positive
displacement grinder pumps shall be protected from freezing when the piping is
installed less than four feet below grade in outside locations.
(i) The discharge shall be installed in
accordance with the manufacturer's installation instructions:
(ii) shall be a minimum of 11/2 inch;
and
(iii) an accessible check valve
and full port shut off valve shall be installed on the discharge piping, and
the discharge shall be properly protected from freezing.
e. Secondary structures and
cabanas located on residential properties which discharge into the sanitary
drainage system or building sewer of the main structure. Piping shall be sized
in accordance with
248
CMR
10.15 but in no case less than two inches
in diameter.
Table 1
Fixture Unit Values for Various Plumbing
Fixtures
|
Type of fixture or group of fixtures
|
Fixture Unit Value
|
|
Bathtub or Tub & Shower Unit
|
2
|
|
Bidet
|
2
|
|
Dental chair unit or cuspidor
|
1
|
|
Dental lavatory
|
1
|
|
Drinking fountain/Water Station
|
1
|
|
Dishwasher, commercial
|
6
|
|
Dishwasher, Residential
|
1
|
|
Floor/trench drain 2-inch
|
4
|
|
Floor/trench drain 3-inch
|
5
|
|
Floor/trench drain 4-inch
|
6
|
|
Kitchen sink Residential (with or without
disposer)
|
2
|
|
Lavatory with 1-1/4" outlet
|
1
|
|
Laundry Connection Residential
|
3
|
|
Laundry/Utility Sink
|
2
|
|
Shower stall Residential
|
2
|
|
Showers (group) per head
|
2
|
|
Sinks:
|
|
Surgeons
|
3
|
|
Flushing rim (with valve)
|
6
|
|
Service Sink with Trap Standard
|
3
|
|
Service Sink with P-Trap
|
2
|
|
Commercial Pot, scullery, etc. (each
section) See Note 1 Below
|
4
|
|
Shampoo
|
2
|
|
Toilet, Tank Type
|
4
|
|
Toilet, Valve Operated
|
6
|
|
Urinal, pedestal, siphon jet blowout
|
6
|
|
Urinal, wall lip
|
4
|
|
Urinal, Waterless
|
1
|
|
Wash sink (circular or multiple) each 20 inches of
usable length
|
1
|
|
Sizes for fixtures not listed
above:
|
|
UA inch or less
|
1
|
|
11/4 inches
|
2
|
|
2 inches
|
3
|
|
21/2 inches
|
4
|
|
3 inches
|
5
|
|
4 inches
|
6
|
Note 1: See
248
CMR 10.15(1)(b)2.d. for
sizing using grease interceptors.
Note 2: See
248
CMR 10.15(2)(b) for method
of computing fixture unit values of devices with continuous or semi-continuous
flows.
Note 3: The size of floor drains shall be determined by the
area of the floor surface to be drained in accordance with
248
CMR 10.10(10)(a).
Table 2
Maximum Loads in Fixture Units for Horizontal Drains
(F.U.)
|
Diameter of drain in
inches
|
Horizontal Branch Drain
(F.U.)
|
Building Drain
|
|
1/8 in./ft. (F.U.)
|
1/4 in./ft. (F.U.)
|
1/2 in./ft. (F.U.)
|
|
11/2
|
3
|
---
|
---
|
---
|
|
2
|
6
|
---
|
---
|
---
|
|
21/2
|
12
|
---
|
---
|
---
|
|
3
|
34*
|
---
|
40*
|
48*
|
|
4
|
160
|
180
|
216
|
250
|
|
5
|
360
|
390
|
480
|
575
|
|
6
|
620
|
700
|
840
|
1,000
|
|
8
|
1,400
|
1,600
|
1,920
|
2,300
|
|
10
|
2,500
|
2,900
|
3,500
|
4,200
|
|
12
|
3,900
|
4,600
|
5,600
|
6,700
|
|
15
|
7,000
|
8,300
|
10,000
|
12,000
|
* Not more than four water closets
Table 3
Maximum Loads in Fixture Units for Soil and Waste Stacks
Having One or Two Branch Intervals
|
Diameter of Stack
(inches)
|
Maximum Load on Stack
(F.U.)
|
|
11/2
|
4
|
|
2
|
8
|
|
21/2
|
20
|
|
3*
|
48
|
|
4
|
240
|
|
5
|
540
|
|
6
|
930
|
|
8
|
2,100
|
|
10
|
3,750
|
|
12
|
5,850
|
|
15
|
10,500
|
*No more than four water closets
Table 4
Maximum Loads in Fixture Units for Any One Branch
Interval on Multistory Soil and Waste Stacks
The table is meant to be used for building with 15 or less
branch intervals.
Please see formula and example below the table for
buildings exceeding 15 branch intervals.
|
Diameter of Stack
|
Number of Branch
Intervals
|
Maximum Total Load for
Stack
|
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
|
2
|
3
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
10
|
|
2 1/2
|
8
|
7
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
----
|
28
|
|
3*
|
20
|
18
|
17
|
16
|
15
|
14
|
13
|
12
|
11
|
10
|
10
|
10
|
10
|
102
|
|
4
|
100
|
90
|
84
|
80
|
77
|
75
|
73
|
72
|
71
|
70
|
69
|
68
|
68
|
530
|
|
5
|
225
|
205
|
190
|
180
|
175
|
170
|
165
|
162
|
159
|
157
|
156
|
154
|
153
|
1,400
|
|
6
|
385
|
350
|
325
|
310
|
300
|
290
|
285
|
280
|
275
|
271
|
268
|
266
|
263
|
2,900
|
|
8
|
875
|
785
|
735
|
700
|
675
|
655
|
640
|
630
|
620
|
612
|
606
|
600
|
594
|
7,600
|
|
10
|
1,560
|
1,405
|
1,310
|
1,250
|
1,205
|
1,170
|
1,140
|
1,125
|
1,110
|
1,095
|
1,180
|
1,075
|
1,062
|
15,000
|
|
12
|
2,435
|
2,195
|
2,045
|
1,950
|
1,875
|
1,825
|
1,790
|
1,755
|
1,730
|
1,705
|
1,685
|
1,670
|
1,655
|
26,000
|
|
15
|
4,375
|
3,935
|
3,675
|
3,500
|
3,380
|
3,280
|
3,210
|
3,150
|
3,110
|
3,060
|
3,030
|
3,000
|
2,975
|
50,000
|
* No more than three water closets In buildings with three-inch
stacks and more than fifteen branch intervals, no single branch interval shall
exceed more than ten fixture units.
Formula to be used for buildings in excess of 15 branch
intervals
N = The permissible load on a stack with one or two branch
intervals as shown in Table 3
Click to
view image
n = Number of branch intervals on the stack to be sized
Example: Stack size = 4"
10 Branch Intervals Fixture Unit per Branch
Click to
view image
(7)
Sizing of Offsets on Stacks
and Vertical Drainage Piping
(a)
Offsets of 450
°
or Less. An offset with a change of direction of 45
° or less from the vertical, may be sized as a straight vertical stack. In
the event a horizontal branch connects to the stack within two feet above or
below the offset, a relief vent shall be installed in accordance with
248
CMR
10.16(2)(d).
See
10.15: Example 1.
(b)
Offsets of More than 45
°. A stack with an offset of more than 45 °
from the vertical shall be sized as a horizontal drain and as follows:
See 10.15:
Example 2
1. The portion of the stack above the offset
shall be sized using
248
CMR
10.15:
Table 3 based on
the total number of fixture units above the offset.
2. The offset shall be sized using
248
CMR
10.15:
Table
2.
3. The portion of the
stack below the offset shall be sized based on the total number of fixture
units on the entire stack above including the offset.
4. In buildings of five stories or more, a
relief vent for the offset shall be installed as required elsewhere in
248
CMR
10.16(2)(d).
a. In no case shall a horizontal branch
connect to the offset or to the stack within two feet above or below the
offset.
10.15 Example 1 Offsets of 45° or less
Click to
view image
10.15 Example 2 Offsets of more than
45°
Click to
view image
(c)
Offsets Above the Highest
Branch. An offset above the highest horizontal branch is an offset
in the stack-vent and shall be considered only as it affects the developed
length of the vent.
(d)
Offsets Below the Lowest Branch. In the case of an
offset in a soil or waste stack below the lowest horizontal branch, there shall
be no change in diameter required if the offset is made at an angle of less
than 45°. If such an offset is made at an angle greater than 45 degrees to
the vertical, the required diameter of the offset and the stack below it shall
be determined using
248
CMR
10.15:
Table
2.
(8)
Drainage Piping Installations.
(a)
See
248
CMR
10.05 for the following:
1. Pitch of horizontal piping.
2. Fittings used to change
direction.
3. Prohibited
fittings.
4. Heel or side inlet
bends.
5. Obstructions to
flow.
(b)
Back to Back Fixtures When Using a Single Fitting.
1.
Horizontal: Shall
by installed with the use of double sanitary wye fittings only to eliminate
throw over.
2.
Vertical: Shall be installed with the use of double
sanitary drainage pattern tee fittings.
See 10.15: Example 2.
Exception: For water closets, double wye fittings may
be used if required by the water closet manufacturer's installation
instructions.
See 10.15: Example 3.
Example 2 Double Sanitary Tee
Click to
view image
Example 3 Double Wye
Click to
view image
(c)
Kitchen Sink Wastes
(Residential).
1. Not less than a
11/2 inch branch waste or waste outlet shall be provided to receive the
fixture drain from a kitchen sink, which shall connect independently to the
sanitary drainage system.
2. A
kitchen sink shall not waste into any horizontal drain smaller than three
inches in diameter receiving discharge from a flat bottom fixture.
3. The roughed-in drain line for final
connection to a kitchen sink shall be installed at a height to permit the
installation of a food waste disposer.
4. A full-size cleanout shall be installed
under all kitchen sinks.
Exception: A two-piece kitchen sink
trap which may be disassembled for use in lieu of a
clean-out.
(d)
Laundries Drains in Multi-Story Buildings. In
buildings where laundries are installed on more than three branch intervals,
the waste line shall be connected to an independent laundry stack.
See 10.15:
Example 4.
1. The independent laundry stacks shall
connect to an independent laundry main drain.
2. The independent laundry main drain shall
connect to the building drain a minimum of 40 pipe diameters upstream and
downstream of any soil or waste stack.
3. A suds relief vent shall connect to the
laundry main drain a minimum of 40 pipe diameters downstream from the base of
the laundry stack. The suds relief vent shall connect to a vent a minimum of
two branch intervals above the base of the laundry stack.
4. The Inspector may permit a variation from
the above requirements when conditions will not allow compliance.
10.15: Example 4 - Laundries Installed on More Than Three
Branch Intervals
|
SUDS PRESSURE RELIEF VENT
|
|
WASTE SIZE
|
RELIEF VENT SIZE
|
|
2"
|
2"
|
|
2"
|
2"
|
|
2-1/2"
|
2"
|
|
3"
|
2"
|
|
4"
|
3"
|
|
5"
|
4"
|
|
6"
|
5"
|
|
8"
|
5"
|
Click to
view image
Click to
view image
Click to
view image
(9)
Sumps and
Ejectors.
(a)
Building Drains Below Building Sewer. Where it is not
possible or practical for a drain to be discharged to the sewer by gravity
flow, the drain shall be discharged into a tightly covered and vented sump,
from which the contents shall be lifted and discharged into the building
gravity drainage system by automatic pumping equipment.
(b)
Sewage Pumps and
Ejectors.
1. In single-family
dwellings, a sewage-ejector sump receiving the discharge of toilets and other
fixtures shall be equipped with a sewage-ejector pump having a full-size
discharge and a minimum discharge capacity of 20 gallons per minute.
2. In all installations other than
single-family dwelling, sewage-ejector pumps shall be equipped with a
full-sized discharge and be sized in conformance with
248
CMR
10.15(10):
Table
5:
Determining Capacities of Sewage
Ejectors.
3. The discharge
piping from all sewage pumps and ejectors shall contain an accessible backwater
or check valve and an accessible full port shut off valve installed downstream
of the backwater or check valve. See 10.15: Example
5.
4. For systems not
determined using 10.15:
Table 5, a variance shall be required.
Exception: Systems designed by a Massachusetts
professional engineer.
10.15: Example 5 Discharge Piping from Sewage
Ejector
Click to
view image
(c)
Macerating Toilet
Systems.
1. All macerating toilet
systems shall be product accepted by the Board and in compliance with ASME
A112.3.4 or CSA B45.9
2. Systems
shall be suitable for the application and installed in accordance with the
product manufacturer's installation instructions.
3. Shall have a minimum three-quarter inch
discharge.
4. With the exception of
toilets, all fixtures connecting to a macerating system shall be properly
trapped and vented prior to connecting to the pumping unit.
(d)
Pneumatic
Ejectors.
1. The air pressure
relief pipe from a pneumatic ejector shall not be connected to the regular
venting system but shall be vented independently to the atmosphere through the
roof.
2. The relief pipe shall be
of sufficient size to relieve air pressure inside ejector atmospheric pressure
within ten seconds but shall be not less than one inch in diameter.
(e)
Grinder
Pumps. Shall be product accepted, installed in accordance with the
manufacturer's installation and with
248
CMR
10.15(6)(b)1.d.
(f)
Duplex
Equipment. Sewage pumps and ejectors, in other than one- or
two-family dwellings receiving the discharge of six or more toilets shall be
provided with duplex pumping equipment.
(g)
Connections to the Building
Drainage System. The discharge piping from a sewage pump or
ejector shall be connected independently to the building drainage
system.
(h) To calculate the
discharge capacities of sewage pumps and ejectors, the following procedures
shall be used.
2. Any installation
that does not meet the requirements of
248
CMR
10.15(9):
Table 5 shall be designed by a Massachusetts professional
engineer.
Table 5
Determining Capacities of Sewage Ejectors
|
Number of toilets to be Served by each
Ejector
|
G.P.M. Discharge of each
Pump
|
|
1
|
20
|
|
2 - 3
|
75
|
|
4 - 5
|
100
|
|
6 - 7
|
125
|
|
8 - 10
|
150
|
|
11 - 15
|
200
|
|
16 - 20
|
250
|
|
21 - 25
|
300
|
|
26 - 30
|
350
|
|
31 - 35
|
375
|
(i)
Ejectors Handling Other
Fixtures. Generally, there will be a certain number of fixtures
other than toilets emptying into the ejector sump. If the total amount of these
fixtures exceeds four times the number of toilets used, the G.P.M. of the
ejector pump should be increased at the rate of three G.P.M. for each fixture
exceeding four times the number of toilets :
Example
|
GPM Pump Discharge of four
Toilets
|
100 GPM
|
|
Number of additional fixtures to be
handled
|
20
|
|
Excess Fixtures as calculated from above 20 - (4 x 4)
= 4
|
4
|
|
Four @ 3 GPM
|
12 GPM
|
|
Correct Sewage Ejector Pump to use
|
112 GPM
|
(j)
Individual Fixture Pumps.
1. Individual fixtures other than toilets,
urinals or similar fixtures may discharge directly into:
a. a fixture mounted pump; or
b. into sumps and receivers with ejectors or
pumps.
2. Individual
fixture pumps may be used for sinks when unusual building structure conditions
prevent the discharge of liquid waste by gravity.
3. Direct-mounted individual fixture pumps
may be manually or automatically operated.
4. The individual fixture pumps shall be
vented in accordance with the manufacturer's instructions. If individual
fixture pumps provide an adequate water seal in accordance with
248
CMR
10.03 additional traps shall not be
required.
(10)
Drainage Fixtures Subject to Backflow.
(a) Backwater valves may be installed in
drain piping which receives the discharge only from fixtures or drains subject
to backflow from the public sewer system. All other drains which are not
subject to backflow shall not drain through a backwater valve. See
10.15: Example 6.
(b)
Materials for Backwater Valves. Backwater valves shall
have all bearing parts of corrosion-resistant material.
(c)
Diameter of Backwater
Valves. Backwater valves, when fully opened shall have an
effective opening not less than that of the pipes to which they are
installed.
(d)
Location
of Backwater Valves. Backwater valves shall be installed so their
working parts will be accessible for service and repairs.
10.15: Example 6 - Backwater Valve
Click to
view image
