hotel domestic water systems

Hotel Domestic Water Systems

Hotel Plumbing Systems Overview

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Domestic Hot Water Recirculation Systems

Domestic Hot Water Systems

Domestic Cold Water Systems

Definitions and Industry Terms

Common Plumbing Definitions

• DCW – Domestic Cold Water

• DHW – Domestic Hot Water

• DHWR – Domestic Hot Water Recirculation

• RP – Recirculation Pump

• TMV – Thermostatic Mixing Valve

• CV – Check Valve

• BFP – Backflow Preventor

• DWH – Domestic Water Heater

• GWH – Gas Fired Water Heater

• EWH – Electric Water Heater

System Types Equipment Water Heaters

Common Plumbing Definitions – Floor Plan

• A floor plan is a drawing to scale, showing a view from above, of the relationships between rooms, spaces, traffic patterns, and other physical features at one level of a structure.

• Floor plans are used in plumbing system design to show the intended routing of piping systems and locations of fixtures.

What is a Floor Plan? Why are Floor Plans Needed?

Notice the piping is routed throughout the building in the general areas it is installed.

Floor Plan Example

Common Plumbing Definitions – Riser Diagram

• Whenever new water or drain lines are to be installed, a plumbing riser diagram is required. A plumbing riser diagram consists of water, drain and vent lines being installed. A riser diagram provides the missing details that cannot be depicted on the floor plans.

• Riser Diagrams indicate all pipe sizes on the water and drainage piping systems and show cleanouts for the sanitary system. They also provide a complete view of the system layout in a condensed manner

What is a Riser Diagram? What missing information is added?

The complete domestic hot water system layout and order is providing complete sizing of the domestic hot water system.

Riser Diagram Example 1

The complete domestic hot water system layout and order is providing complete sizing of the domestic hot water system.

Riser Diagram Example 2

• Source of water is either municipal or on site well.

• Cold water enters in a service type room. Mechanical room, meter room, etc.

Cold Water Systems

• For municipal systems, a water meter and main shut off are the first two items on the system.

• Cold water pressure is typically between 30 and 80 PSI for a commercial building. Anything under 30 PSI and flush valves have operational issues. The code limits the maximum pressure at any fixture to 80 PSI.

Cold Water Systems

• When the incoming water pressure is too low a booster pump is used to increase the pressure in the system

• Some Buildings do not have enough pressure to operate the most remote fixtures based upon their incoming water pressure.

Cold Water Systems


• All domestic hot water is supplied from the cold water system

• Industry standards is to heat the domestic hot water to above 140° F

• Point of use

• Central Generation

• Hybrid

• Instantaneous

• Semi Instantaneous

• Storage

Generation Types of Systems Types of Water Heaters

• Installed on local fixtures. Can be one per bathroom group, one per fixture, etc. No central mixing valve in this scheme

• Typically one or two fixtures are served by one water heater.

• These systems are used when there are remote fixtures and additional domestic hot water piping is not desired throughout the building.

Point of use

• Located in one place and piped through out the building at one temperature. Typically located in a mechanical or water service room.

• Master or Main TMV is located here. This is the last place the domestic hot water temperature is adjusted before going to the guest rooms.

Central Generation

• An example of centrally located domestic hot water heaters.

• Typically the system is comprised of a few smaller water heaters. This allows for some system redundancy when there is a failure or repair required.

Central Generation

• Water is heated to temperature at the rate of demand through the water heater. Can be used as point of use or as a central system.

• These can be point of use or centrally located

• Current trends are using many of these units with a small storage tank.

Instantaneous Water Heating

• Semi-instantaneous water heaters are sized to overheat the water, and they utilize a temperature-actuated mixing valves on the outlet of the water heater to provide a consistent outlet temperature to the hot water distribution system. This allows for a constant hot water temperature as flow through the heat exchanger fluctuates with demand.

Semi Instantaneous Water Heating

• Direct Fired – The water is heated directly in the storage tank.

• Indirect Fired – Water is heater through a separate energy source and pumped between the source and the storage tanks.

• Large amounts of hot water are stored. Energy input loads are typically smaller than instantaneous and semi instantons system. Storage sizes for hotels can range from 500 to 1000 gallons

Storage Type

Domestic Hot Water Systems Energy Sources

Steam – Steam is produced from a

boiler or an off site utility

Can be #2 fuel oil…aka diesel. Also

can be kerosene. Both are delivered by

truck

Can be natural gas or LP gas. Natural gas is typically connected

form the street and LP is delivered by truck.

Uses the suns radiation to heat water through

a exterior heat exchanger (solar panel)

Provided by a local utility.

Electric type water heater with a heat

pump added. Acts like an air conditioner in

reverse.

Heat Pump/Hybrid ElectricitySolarGasOil Steam

• Hot water is recirculated in central domestic hot water systems to make up for the heat loss through of the piping distribution system. The intent to maintain a minimum temperature in the entire domestic hot water system. Industry standard is a temperature above 120° F.

• Typically any fixtures that are more than 50 feet from the hot water generation will have a recirculation line. Plumbing codes have minimum standards for this. (varies by state and local jurisdictions)


• A pump is provided in the mechanical room, circulating the domestic hot water back through the water heater to add back in the energy lost in the domestic hot water system.

• They are sized based upon the heat loss of the piping to maintain the temperature of the domestic hot water system. Typically the return temp is 5 to 10 degrees cooler than the domestic hot water.


Legionella

• Legionnaires’ disease is a serious type of pneumonia (lung infection) caused by Legionella bacteria.

• To reduce the risk of biological growth.

• Shower Heads and sink faucets

• Hot water tanks and heaters

• Large plumbing systems

• It does not prevent any growth of bacteria or replace other legionella prevention systems.

• It can used by hotels as an additional tool in their legionella prevention program.

What is it?Parts of Hot Water Systems that

it grow or spread What does SWM do?

Hotel Domestic Hot Water System Key Temperatures

• Above 140°-150° F

• To reduce the risk of biological growth.

• Many domestic water heaters and storage tank warranties are voided at 160° F

• Between 120°-130° F

• Over 130° F increases the risk of scalding.

• Under 120° F is too low to assume hot water recirculation temperatures are hot enough

• Above 120° F

• This is the minimum preferred temperature to reduce the risk of biological growth in the domestic hot water system.

Hot Water Generation and Storage

Hot Water Supply to Guest Rooms

Hot Water Recirculation Temperature Range

Questions?

© 2019 SYMMONS, INC.25

Hotel Domestic Water Systems


Hotel Plumbing Systems Overview

Domestic Hot Water

Recirculation Systems

Domestic Hot Water

Systems

Domestic Cold Water

Systems

Definitions and Industry

Terms


Common Plumbing Definitions

• DCW – Domestic Cold

Water

• DHW – Domestic Hot

Water

• DHWR – Domestic Hot

Water Recirculation

• RP – Recirculation Pump

• TMV – Thermostatic

Mixing Valve

• CV – Check Valve

• BFP – Backflow Preventor

• DWH – Domestic Water

Heater

• GWH – Gas Fired Water

Heater

• EWH – Electric Water

Heater

System Types Equipment Water Heaters


Common Plumbing Definitions – Floor Plan

• A floor plan is a drawing to scale,

showing a view from above, of the

relationships between rooms, spaces,

traffic patterns, and other physical

features at one level of a structure.

• Floor plans are used in plumbing system

design to show the intended routing of

piping systems and locations of fixtures.

What is a Floor Plan? Why are Floor Plans Needed?


Notice the piping is routed throughout the

building in the general areas it is installed.

Floor Plan Example


Common Plumbing Definitions – Riser Diagram

• Whenever new water or drain lines are to

be installed, a plumbing riser diagram is

required. A plumbing riser

diagram consists of water, drain and vent

lines being installed. A riser diagram

provides the missing details that cannot

be depicted on the floor plans.

• Riser Diagrams indicate all pipe sizes on

the water and drainage piping systems

and show cleanouts for the sanitary

system. They also provide a complete

view of the system layout in a condensed

manner

What is a Riser Diagram? What missing information is added?


The complete domestic hot water system

layout and order is providing complete sizing

of the domestic hot water system.

Riser Diagram

Example 1


The complete domestic hot water system

layout and order is providing complete sizing

of the domestic hot water system.

Riser Diagram

Example 2


• Source of water is either municipal or on site

well.

• Cold water enters in a service type room.

Mechanical room, meter room, etc.

Cold Water Systems


• For municipal systems, a water meter and

main shut off are the first two items on the

system.

• Cold water pressure is typically between 30

and 80 PSI for a commercial building. Anything

under 30 PSI and flush valves have

operational issues. The code limits the

maximum pressure at any fixture to 80 PSI.

Cold Water Systems


• When the incoming water pressure is too low a

booster pump is used to increase the pressure

in the system

• Some Buildings do not have enough pressure

to operate the most remote fixtures based

upon their incoming water pressure.

Cold Water Systems



• All domestic hot water is

supplied from the cold

water system

• Industry standards is to

heat the domestic hot

water to above 140° F

• Point of use

• Central Generation

• Hybrid

• Instantaneous

• Semi Instantaneous

• Storage

Generation Types of Systems Types of Water Heaters


• Installed on local fixtures. Can be one per

bathroom group, one per fixture, etc. No

central mixing valve in this scheme

• Typically one or two fixtures are served by one

water heater.

• These systems are used when there are

remote fixtures and additional domestic hot

water piping is not desired throughout the

building.

Point of use


• Located in one place and piped through out

the building at one temperature. Typically

located in a mechanical or water service room.

• Master or Main TMV is located here. This is

the last place the domestic hot water

temperature is adjusted before going to the

guest rooms.

Central Generation


• An example of centrally located domestic hot

water heaters.

• Typically the system is comprised of a few

smaller water heaters. This allows for some

system redundancy when there is a failure or

repair required.

Central Generation


• Water is heated to temperature at the rate of

demand through the water heater. Can be

used as point of use or as a central system.

• These can be point of use or centrally located

• Current trends are using many of these units

with a small storage tank.

Instantaneous Water

Heating


• Semi-instantaneous water heaters are sized to

overheat the water, and they utilize a

temperature-actuated mixing valves on the

outlet of the water heater to provide a

consistent outlet temperature to the hot water

distribution system. This allows for a constant

hot water temperature as flow through the heat

exchanger fluctuates with demand.

Semi Instantaneous

Water Heating


• Direct Fired – The water is heated directly in

the storage tank.

• Indirect Fired – Water is heater through a

separate energy source and pumped between

the source and the storage tanks.

• Large amounts of hot water are stored. Energy

input loads are typically smaller than

instantaneous and semi instantons system.

Storage sizes for hotels can range from 500 to

1000 gallons

Storage Type


Domestic Hot Water Systems Energy Sources

Steam – Steam is

produced from a

boiler or an off site

utility

Can be #2 fuel

oil…aka diesel.

Also can be

kerosene. Both are

delivered by truck

Can be natural gas

or LP gas. Natural

gas is typically

connected form the

street and LP is

delivered by truck.

Uses the suns

radiation to heat

water through a

exterior heat

exchanger (solar

panel)

Provided by a local

utility.

Electric type water

heater with a heat

pump added. Acts

like an air

conditioner in

reverse.

Heat

Pump/Hybrid

ElectricitySolarGasOil Steam


• Hot water is recirculated in central domestic

hot water systems to make up for the heat loss

through of the piping distribution system. The

intent to maintain a minimum temperature in

the entire domestic hot water system. Industry

standard is a temperature above 120° F.

• Typically any fixtures that are more than 50

feet from the hot water generation will have a

recirculation line. Plumbing codes have

minimum standards for this. (varies by state

and local jurisdictions)

Domestic Hot Water



• A pump is provided in the mechanical room,

circulating the domestic hot water back

through the water heater to add back in the

energy lost in the domestic hot water system.

• They are sized based upon the heat loss of

the piping to maintain the temperature of the

domestic hot water system. Typically the

return temp is 5 to 10 degrees cooler than the

domestic hot water.

Domestic Hot Water



Legionella

• Legionnaires’ disease is a

serious type of pneumonia

(lung infection) caused by

Legionella bacteria.

• To reduce the risk of

biological growth.

• Shower Heads and sink

faucets

• Hot water tanks and

heaters

• Large plumbing systems

• It does not prevent any

growth of bacteria or

replace other legionella

prevention systems.

• It can used by hotels as

an additional tool in their

legionella prevention

program.

What is it?Parts of Hot Water Systems

that it grow or spreadWhat does SWM do?


Hotel Domestic Hot Water System Key Temperatures

• Above 140°-150° F

• To reduce the risk of

biological growth.

• Many domestic water

heaters and storage tank

warranties are voided at

160° F

• Between 120°-130° F

• Over 130° F increases the

risk of scalding.

• Under 120° F is too low to

assume hot water

recirculation temperatures

are hot enough

• Above 120° F

• This is the minimum

preferred temperature to

reduce the risk of

biological growth in the

domestic hot water

system.

Hot Water Generation and

Storage

Hot Water Supply to Guest

Rooms

Hot Water Recirculation

Temperature Range


Questions?

hotel domestic water systems

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