Hot Water Calculation.pdf

7/27/2019 Hot Water Calculation.pdf

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1. Introduction 3

2. Plumbing Water Services 4

2.1 Service Water 5

2.2 Potable Water 6

2.3 Water Supply Fixture Units (WSFU)s 7

2.4 Electric Water Heater 8

3. Drainage System 22

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Table Of Contents


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1. Introduction

All plumbing works shall be designed in accordance with the project specifications together with the Uniform

Plumbing Code (UPC).

1.1 Project Specifications

S-B00-1340-012 - Design Specification For Process Buildings

S-B00-1340-101 - Building - General Requirement

S-B00-1340-301 - Specification For Plumbing And Piping For Buildings

Reference Drawings

V-3140-002-4-401-42 - Plumbing Plan & Details / Water Supply First Floor Zone 1 Layout

V-3140-002-4-402-42 - Plumbing Plan & Details / Water Supply First Floor Zone 2 Layout

V-3140-002-4-403-42 - Plumbing Plan & Details / Water Supply First Floor Zone 1 Details

V-3140-002-4-404-42 - Plumbing Plan & Details / Water Supply First Floor Zone 2 Details

V-3140-002-4-405-42 - Plumbing Plan & Details / Water Supply Second Floor Zone 1 Layout

V-3140-002-4-406-42 - Plumbing Plan & Details / Water Supply Second Floor Zone 2 Layout

V-3140-002-4-407-42 - Plumbing Plan & Details / Water Supply Second Floor Zone 1 Details

V-3140-002-4-408-42 - Plumbing Plan & Details / Water Supply Second Floor Zone 2 Details

V-3140-002-4-409-42 - Plumbing Plan & Details / Water Supply First Floor Zone 1 Isometric

V-3140-002-4-410-42 - Plumbing Plan & Details / Water Supply First Floor Zone 2 Isometric

V-3140-002-4-411-42 - Plumbing Plan & Details / Water Supply Second Floor Zone 1 Isometric

V-3140-002-4-412-42 - Plumbing Plan & Details / Water Supply Second Floor Zone 2 Isometric

V-3140-002-4-413-42 - Plumbing Plan & Details / Drainage System First Floor Zone 1 Layout

V-3140-002-4-414-42 - Plumbing Plan & Details / Drainage System First Floor Zone 2 Layout

V-3140-002-4-415-42 - Plumbing Plan & Details / Drainage System First Floor Zone 1 Details

V-3140-002-4-416-42 - Plumbing Plan & Details / Drainage System First Floor Zone 2 Details

V-3140-002-4-417-42 - Plumbing Plan & Details / Drainage System Second Floor Zone 1 Layout

V-3140-002-4-418-42 - Plumbing Plan & Details / Drainage System Second Floor Zone 2 Layout

V-3140-002-4-419-42 - Plumbing Plan & Details / Drainage System Second Floor Zone 1 Details

V-3140-002-4-420-42 - Plumbing Plan & Details / Drainage System Second Floor Zone 2 Details

V-3140-002-4-421-42 - Plumbing Plan & Details / Drainage System First Floor Zone 1 Isometric

V-3140-002-4-422-42 - Plumbing Plan & Details / Drainage System First Floor Zone 2 Isometric

V-3140-002-4-423-42 - Plumbing Plan & Details / Drainage System Second Floor Zone 1 Isometric

V-3140-002-4-424-42 - Plumbing Plan & Details / Drainage System Second Floor Zone 2 Isometric

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2. Plumbing Water Services

Potable Water and Service Water shall be supplied to Operations Centre

(BXK-02) Building.

The water supply fixture units (WSFU) method for sizing network within

(BXK-02) building shall be utilized, as per UPC, Table A-2.

The flow rates are calculated from UPC charts A-2 & A-3, based on the

WSFU for each part of the network.

A maximum velocity of 3.0 m/s is allowed as per A61 of UPC.

The flow requirement for AHU 02 humidifier is l/s.

The flow requirement for AHU 03 humidifier is l/s.

Service Water is provided only for flush valves of the water closets & bib taps.

All other fixtures are provided with Potable Water.

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2.1 Service Water - Into Mechanical/Electrical Room 2

The following can be noted for pressure limitations:

Minimum pressure at flush valve = 30 Psi (207 kPa)

Pressure losses in the network:

Minimum residual pressure = 207 kPa

Elevation Differnece = 30 kPa

System Pressure Loss

115m x 0.5 kPa/m (avg) x 1.5 = 86.25 kPa

TOTAL 323.25 kPa

With 10% Margin = 356 kPa

Thus minimum pressure required in the SW network shall be356 kPa (51.6 Psi)

Note: Pressure available is 5 bar (72.5 Psi).

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2.2 Potable Water - Into Mechanical/Electrical Room 2

The following can be noted for pressure limitations:

Minimum pressure at lavatory = 15 Psi (103 kPa)

Pressure losses in the network:

Minimum residual pressure = 103 kPa

Elevation Differnece = 15 kPa

System Pressure Loss

110m x 0.5 kPa/m (avg) x 1.5 = 82.5 kPa

TOTAL 200.50 kPa

With 10% Margin = 221 kPa

Thus minimum pressure required in the PW network shall be 221 kPa (32.1 Psi)

Note: Pressure available is 5 bar (72.5 Psi).

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2.3 Water Supply Fixture Units (WSFU)s

Table - 1 Incoming (Mechanical/Electrical Room 2)

WSFU/Fixture Total WSFU/Fixture HW* Total

Water Closet Western Type 4 5 20

Water Closet Eastern type 22 5 110

Lavatory 30 0.75** 0.75** 45

Janitors Sink 8 3 24

Kitchen Sink 5 1.125** 1.125** 67.5

Hand spray 26 2 52

Urinal 18 5 90

Humidifier 2 0.5 1

Hose Bibb* 2 2.5 3.5

Water Cooler 2 0.5 1

Total 247.5 166.5

* HBs total cold water fixture units = (1x2.5)+(1x1) = 3.5 as per table A-2 of UPC

Based on criteria of velocity and pressure limitations, the pipe work within

the building has been sized using charts A-3 of UPC.

* HW Stands For Hot Water

** Combined PW/HW Fixture Units (PW or HW WSFU is of the Total WSFU.)

As per charts A-3 of UPC:

Service Water (Mechanical/Electrical Room 2) = 247.5 WSFU = 6.342 l/s =40mm

Potable Water (Mechanical/Electrical Room 2) = 166.5 WSFU = 3.681 l/s = 40mm

Incoming (Mechanical/Electrical Room 2)

A 75mm (3" diameter) Service water pipe is required at the inlet to the building

and a 50mm (2" diameter) Potable water pipe is required at the inlet to the building

Both sizes are equal to the tie-in sizes.

7

FixturePWSW

Qty


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2.4 Electric Water Heater

Reference to ASHRAE Handbook-Applications, Chapter 49 for "Service

Water Heating" (Table 10, Hot water demand of various types of fixtures

and buildings).

The building is served by fourteen electric water heaters.

As shown on the layout drawings.

Hot water demand as per Table 3:

Table 3

Electric Water Heater 1 - Toilet Male 1

Lavatory 4

TOTAL

Demand Factor = 0.3

Storage Factor = 2

Maximum Possible Demand = 92 l/hr

Probable Maximum Demand = 92 x 0.3 = 27.6 l/hr = 0.00767 l/s

Take 27.6 l/hr as it is > 23 l/hr

Storage Capacity Required = 27.6 x 2 = 55.2 Litres.

Say 60 Litres

Heating Capacity (kW) = 4.2 x 0.00767 x (60-10) = 1.611 kW

Say 2 kW

(Based on T = 50C, incoming water supply 10C, outgoing water supply 60C.)

Therefore, an electrical water heater with minimum 60 Litres (15.85 USG)

storage capacity and 2 kW electric heating coil will be sufficient.

Accordingly, select water heater and install in the Toilet Male 1.

(Note: 3 kW electric water heater to be provided)

8

23 92

92

Hot Water Demand

(Litre/hr)Fixture Qty

Total Hot Water

(Litre/hr)


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Electric Water Heater 2 - Toilet Female 1

Hot water demand as per table 4:

Table 4 - Toilet Female 1

Lavatory 4

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 60 Litres


Say 2 kW




Accordingly, select water heater and install in the Toilet Female 1.


9

23 92

92

Fixture QtyHot Water Demand

(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 3 - Toilet Female 2


Table 5 - Toilet Female 2

Lavatory 3

TOTAL

Demand Factor = 0.3

Storage Factor = 2



Take 23 l/hr as it is > 20.7 l/hr

Storage Capacity Required = 23 x 2 = 46 Litres.

Say 50 Litres


Say 1.5 kW



storage capacity and 1.5 kW electric heating coil will be sufficient.



10

23 69

69


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 4 - Toilet Male 1


Table 6 - Toilet Male 1

Lavatory 3

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 50 Litres


Say 1.5 kW






11

Total Hot Water

(Litre/hr)

23 69

69


(Litre/hr)


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Electric Water Heater 5 - Pantry 1


Table 7 - Pantry 1

Pantry Sink 1

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 80 Litres


Say 2.5 kW




Accordingly, select water heater and install in the Pantry 1.


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(Litre/hr)

Total Hot Water

(Litre/hr)

38 38

38


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Electric Water Heater 6 - Pantry 2


Table 8 - Pantry 2

Pantry Sink 1

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 80 Litres


Say 2.5 kW






13

38 38

38


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 7 - Second Floor Toilet Male 1


Table 9 - Second Floor Toilet Male 1

Lavatory 4

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 60 Litres


Say 2 kW






14

23 92

92


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 8 - Second Floor Toilet Female 1


Table 10 - Second Floor Toilet Female 1

Lavatory 4

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 60 Litres


Say 2 kW






15

23 92

92


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 9 - Second Floor Toilet Female 2


Table 11 - Second Floor Toilet Female 2

Lavatory 3

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 50 Litres


Say 1.5 kW






16

23 69

69


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 10 - Second Floor Toilet Male 2


Table 12 - Second Floor Toilet Male 2

Lavatory 3

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 50 Litres


Say 1.5 kW






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23 69

69


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 11 - V.I.P Toilet


Table 13 - V.I.P Toilet

Lavatory 2

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 50 Litres


Say 1.5 kW




Accordingly, select water heater and install in the V.I.P Toilet.


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23 46

46


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 12 - V.I.P Pantry


Table 14 - V.I.P Pantry

Pantry Sink 1

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 80 Litres


Say 2.5 kW




Accordingly, select water heater and install in the V.I.P Pantry.


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38 38

38


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 13 -Pantry 1


Table 15 - Pantry 1

Pantry Sink 1

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 80 Litres


Say 2.5 kW






20

38 38

38


(Litre/hr)

Total Hot Water

(Litre/hr)


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Electric Water Heater 14 -Pantry 2


Table 16 - Pantry 1

Pantry Sink 1

TOTAL

Demand Factor = 0.3

Storage Factor = 2





Say 80 Litres


Say 2.5 kW






21

38 38

38


(Litre/hr)

Total Hot Water

(Litre/hr)


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3.0 DRAINAGE SYSTEM.

The Drainage fixtures units (DFU) method for sizing the drainage and vent

system and shall be applied as per UPC table 7.3.

Tables 7.5 to 7.8 for (DFU) shall be used for sizing the sanitary sewer and

vent pipework at a slope of 2%.

Two floor drains shall be provided in the HVAC room, connected to a

100mm drain and 50mm dia vent pipe.

Condensate drains from AHUs discharge into floor drains FD through a 50mm dia pipe

with a drain trap & funnel arrangement.

Drainage fixtures units assigned for each fixture is shown in table 2

DFUs and pipe sizes are shown on the drawings

BXK-02 Drainage

Discharge pipes from Water closets and floor gullies discharge to the below slab

drainage system via 100mm dia drain pipe, wall hung lavatory basins & sinks discharge to the

below slab drainage via 50mmdia drain pipe.

Table 2 - Drainage Fixture Units

WWC Water Closet Western 6 22 132

EWC Water Closet Eastern 6 4 24

LAV Wall hung Lavatory 1 30 30

JS Janitor Sink 2 8 16

FD Floor Drain 4 53 212

UR Urinal 2 18 36

KS Kitchen Sink 2 5 10

DF Drinking Fountain 0.5 2 1

Total 461

As per Table 7-4 of Uniform Plumbing Code,

the drainage pipe minimum size for 461 units that incorporates a WWC is 100mm dia.

The vent pipe size is 75mm dia.

Mechanical / Electrical Room 1

Reference FixtureDrainage

Fixture Units

Quantity of

Fixtures

Total Drainage

Fixture Units


Total 20

A 100mm dia pipe shall be provided from the Mechanical / Electrical Room 1 discharging

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Quantity of

Fixtures

Total Drainage

Fixture units

into the sanitary sewer manhole to the sanitary sewer line.


Fixture Units


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Mechanical / Electrical Room 2


Fixture Units

Quantity of

Fixtures

Total Drainage

Fixture Units


Total 12

A 100mm dia pipe shall be provided from the Mechanical / Electrical Room 2 discharging

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into the sanitary sewer manhole to the sanitary sewer line.

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