WaterSense
-I«ter«afiooal Institute
for Sustainable Laboratories®
Best Practices Guide
Water Efficiency in Laboratories
MAY 2022
Table of Contents
Introduction .2
Parti: Lab-Specific Water Savings Opportunities 3
Water Management 3
Laboratory Equipment Best Practices 6
Laboratory Design 18
Part II: Water Savings Opportunities Not Specific to Labs 21
Cooling Towers 21
Steam Boiler Water Efficiency 27
Other Typical Building Water Loads 30
Alternative Water Sources ,., ,., ,., , , ,... 32
Acknowledgements............................................................................. 37
References................................................................................... 37
Additional Resources 39
Contact I2SL: www.i2sl.org • infe(Sl2sl.org • 703.841.5484
fiSL is dedicated to advancing sustainable Jabotfltories,globattyl
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Water Efficiency in Laboratories
Trends in the Consumer Price Index (CPI) for utilities and transportation
00 O CM Tf CO CO O
O i- i- i- i- i- CM
O O O O O O O
CM CM CM CM CM CM CM
¦Water & sewer (1953)
-Cable/sat. tv (1984)
-Garbage (1985)
Postage (1935)
CPI (1983=100)
Fuel oil (1935)
-Electricity (1913)
Natural gas (1935)
-CPI (1997=100)
- Landline tel. (2009=100)
- Internet (1997=100)
-Wireless (1997=100)
-Utilities & transport.
(1957)
Source: IPU-MSU based on BLS data.
Figure 1. Trends in the Consumer Price Index for Utilities and Transportation. Figure courtesy of Janice A. Beecher of the
Institute of Public Utilities at Michigan State University.
Introduction
Most laboratory buildings in the United States
use significantly more water per square foot than
typical commercial buildings do. Compared to
commercial buildings of a similar size, a laboratory
can use five times as much potable water (Daniel
Watch and Deepa Tolat, 2016). However, that
means there are a variety of opportunities for
laboratories to make cost-effective improvements
in water efficiency, whether in special lab process
equipment, cooling towers, steam boilers, or other
building systems. With more frequent and intense
droughts and water shortages, some states and
local jurisdictions have adopted aggressive water
reduction targets, and laboratories are responding
with water-saving efforts that also reduce energy
and operating costs—and even increase resiliency.
Water efficiency can also help laboratories offset
rising water and sewer costs. Since 2001, water and
sewer costs have increased at a rate nearly three
times greater than the rate of inflation (Black and
Veatch Management Consulting, 2021). As shown
in Figure 1, this rate of increase far outpaces that of
other public utilities, including electricity, natural
gas, and waste disposal.
Developed in collaboration with the U.S.
Environmental Protection Agency's (EPA's)
WaterSense® program, this document is one of a
series of best practices guides the International
Institute for Sustainable Laboratories (I2SL)
published to provide information about
technologies and practices to use in designing,
constructing, and operating safe, sustainable,
high-performance laboratories. This guide
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Water Efficiency in Laboratories
highlights best practices for laboratory water
management in particular and potable water use
reduction in general, including:
• Water management and monitoring;
• Understanding and targeting efficiency in
specialized laboratory equipment;
• Designing for efficiency;
• Minimizing cooling demand and optimizing
cooling tower and boiler operations;
• Improving efficiency within other building
water systems; and
• Reusing water or identifying alternative
sources.
For more information about saving water in
offices and other facilities, review WaterSense at
Work: Best Management Practices for Commercial
and Institutional Facilities, a comprehensive guide
for building owners and managers pursuing
water efficiency (EPA).
PART I: LAB-SPECIFIC WATER SAVINGS
OPPORTUNITIES
Water Management
In laboratories, water management planning
involves understanding current water use,
identifying and implementing efficiency
measures, and sustaining long-term savings
through the following steps:
• Assessing major water uses within the
facility and lab processes
Establishing a water balance
Establishing water reduction goals
Creating and implementing an action plan
Dedicating staff and resources to pursue
efficiency
Metering and monitoring water use,
including benchmarking
Communicating goals and educating staff
on water-efficient behaviors
Sanitary
(11%)
Lab Processes &
Misc. Lab Water
(28%)
Single-Pass Cooling
Misc. HVAC/
Mechanical Room
(2%)
Reverse Osmosis
Reject
(1%)
Steam Sterilizers
(1%)
Cooling Tower Make-Up
(38%)
Figure 2. Typical EPA laboratory building water use, based on
data collected during water assessments conducted atEPA's
laboratories between 2011 and 2019.
Conducting a Water Assessment and
Establishing a Water Balance
A water assessment is a good place to start
to: establish annual water use; collect detailed
information on major water-using fixtures,
equipment, systems, and processes; create a
facility water balance that shows the sources
and uses of water on a site; and identify water
conservation measures that can be pursued
to reduce laboratory water and energy use
and operating costs. Figure 2 shows water
usage for a typical EPA-operated laboratory.
However, laboratories have unique water usage
characteristics based on their size, function, and
research needs; therefore, a water assessment is
beneficial in understanding end uses of water of a
specific laboratory.
A lab water assessment should collect specific
equipment or process information (e.g., flow
rates, operating frequency, set points, nameplate
capacity) that will help estimate water use. The
water quality required for each use can also be
included, since certain processes and systems
do not require potable water and can present
opportunities for reuse.
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Water Efficiency in Laboratories
To develop a water balance, determine whether
known water purchases equal known usage. If
these two are in balance, look for opportunities for
greater efficiency in each major usage category and
determine whether water from one process can be
used elsewhere cost effectively If purchases and
usage do not balance, however, more investigation
is needed. A thorough review can help laboratory
managers fill in any missing information and
discover the source of the imbalance.
Well-managed facilities can usually
account for 85% to 95% of the water
they purchase.
Following are some tips for determining where a
lab's water use may be out of balance:
• Check grounds and facilities for water or
steam leaks in piping, distribution, condenser
water, irrigation systems, or other equipment.
• Check the facility's main water meter at night
and again in the morning to see if there is
a large amount of unexplained usages that
indicates a leak in the system.
• Review utility bills (about 2 years' worth) to
understand trends in water use over time.
• Complete a detailed survey of staff and
equipment to identify or verify the principal
water users and water-using equipment.
• Ask researchers and facility staff how their
equipment is being used to determine if
actual usage is higher than original estimates.
• Understand the lab's water use from cooling
tower and boiler blowdown and reverse
osmosis treatment, which can be significant
sources. Water-quenching devices used
for hot condensate and blowdown can
also use a lot of water, especially if they
operate continuously without a temperature-
controlled solenoid to limit use.
Goal-Setting and Staff Planning
Following a water assessment, you can create an
action plan with goals and targets to reduce water
use. Once you have a plan in place, it's important to
assign staff who will be responsible for supporting
water management activities, such as: collecting
and tracking water meter and utility billing data;
inventorying water-using systems and laboratory
equipment; managing the execution of water
efficiency projects; and handling communications
and education of researchers and other lab staff.
Assigned staff, such as operations and maintenance
workers, should check water-using systems and
appliances on a regular basis as part of daily
or weekly facility walk-throughs. This can help
identify leaks or other malfunctioning equipment.
For example, cooling tower make-up or boiler
tempering valves that are stuck open are common
problems that can be identified during frequent
facility walks of mechanical spaces and labs, while
leaking irrigation system pipes can be spotted
during an exterior walk-through. The Federal
Energy Management Program (FEMP) has
developed water evaluation tools, including data
collection forms and a water balance tool, to assist
facility staff with water management.
Metering and Monitoring Water Use
Water use should be monitored regularly to
establish use trends and identify potential leaks
or other inefficiencies. Water meters should be
installed at the facility level. Submeters should
be installed on major water-using systems (e.g.,
cooling towers, steam boilers, irrigation systems,
specialized water treatment systems) and on
alternative water systems (e.g., reclaimed water
systems). A good rule of thumb is to submeter any
process using more than 10% of total annual water
consumption, or, in larger labs, 1,000 gallons or
more per day or 100,000 gallons or more per year.
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Water Efficiency in Laboratories
Water use data from meters and submeters should
be collected and tracked regularly. ENERGY STAR®
Portfolio Manager® is a free utility management
tool that can assist with tracking water
consumption. If feasible, meters and submeters
should be integrated into a centralized building
management system or building automation
system, which allows more frequent data
collection and analysis. These systems allow facility
management staff to set alarms if leaks or excessive
use is detected. Make sure staff are assigned to
review data at least monthly to understand trends,
look for anomalies, and respond to preset alarms or
notifications that may indicate a leak.
Use the water use information to compare your
lab's water performance to other facilities of the
same type or function. Benchmarking requires
that overall laboratory or process water use be
divided by some meaningful denominator, such as
conditioned square feet or output. Lab managers
can use I2SL's Laboratory Benchmarking Tool
(LBT) to evaluate how their water use compares
to other similar facilities in terms of gallons of
water per square foot of laboratory space per year
(also referred to as water use intensity or WUI), or
gallons per researcher and employee per day. If
facility data are already collected in ENERGY STAR
Portfolio Manager, it can be imported into the LBT.
Over time, this benchmarking tool will become
more robust as more laboratories enter their water
data at https://lbt.i2sl.orcr.
Figure 3 shows the spread of laboratory WUI
from two datasets. The bar to the left represents
average WUI from 2015-2017 for 34 buildings
with "good" and fully metered data from the
Cambridge Compact Net Zero Labs Work Group's
Lab Benchmarking Report: Phase 2. One laboratory
with reported WUI greater than 200 gallons/square
foot/year was removed. The bar to the right shows
average WUI for laboratories that submitted data to
the LBT (as of November 10, 2021). One laboratory
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Figure 3. Chart showing laboratory water use intensity from
two datasets. The boxes represent the upper and lower
quartiles around the median. The "X" shows the mean. The
lines extending from the boxes indicate variability outside of
the upper and lower quartiles. Additional data points beyond
the lines are considered outliers.
with reported WUI greater than 800 gallons/square
foot and one laboratory with reported WUI of 0
were omitted.
Communicating With Employees
Since the behavior of researchers and other staff
can affect a facility's water use, it's important to
communicate your overall water reduction goals
and specific steps staff can take to help meet them.
For example, outreach materials, building signage,
and training should emphasize the importance
of reporting any leaks occupants see in the
building, and include a point of contact (facility or
maintenance management staff) who can resolve
the leak quickly. Leaks are the ultimate water waste,
so communicating to building occupants, custodial
staff, and others who interact frequently with
different water-using systems will help demonstrate
that water management is important within the
facility.
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Laboratory Equipment Best Practices
Laboratories have unique missions that often
require special processes and equipment, many
of which can be water-intensive, including: water
treatment systems; sterilization equipment; vacuum
systems; glassware, instrument, cage, and/or rack
washers; vivarium watering systems; fume hoods;
humidiflcation systems; and photography/x-ray
equipment.
Equipment Cooling
Single-pass systems use approximately 40 times
more water than a cooling tower operating at five
cycles of concentration to remove the same heat
load.
Eliminating single-pass cooling offers
laboratories a significant opportunity
for water and cost savings.
Lab equipment associated with single-pass cooling
using potable water includes: point-of-use chillers
or other refrigeration systems; condensers;
air conditioners; air compressors; vacuum
pumps; ice machines; electron microscopes;
gas chromatographs; mass spectrometers; and
GAT scanners and X-ray equipment. Sometimes,
research staff order and install equipment that
requires cooling without consulting facility
management, and therefore overlook opportunities
for tie-in to centralized chilled water systems.
The best way to reduce water associated with
single-pass cooling is to either switch to air-cooled
systems or use a process or cooling water loop.
Laboratory facilities with water-side heat recovery
such as a heat recovery heat pump/chiller can even
reclaim waste heat from lab equipment for reheat
elsewhere in the building.
Efficiency and Safety Gains From Air-
Cooled Condensers
Using air-cooled (also known as waterless);
condensers within chemistry labs for synthetic
experiments that require reflux and distillation
can provide a multitude of benefits. Air-cooled
condensers eliminate up to 1 gallon of water per
minute compared to a water-cooled condenser unit.
(Grist, Perkins, and Barber, 2013). Because many labs-
require multiple condensers, the volume of water
and associated water and sewer costs to support
these research activities can add up!
Air-cooled condensers also reduce risk of laboratory
flooding, which can have costly consequences for the
facility and research team. (University of Colorado
[CU] Boulder). They can also be easier to set up, as
they do not require tubing or connectors for water
cooling. This leaves more time and lab space for
other research activities (Radleys).
Example waterless condenser from CU Boulder.
Air Cooling
Many types of equipment used in laboratories (e.g.,
vacuum pumps, ice machines, condensers) have
air-cooled models readily available. Laboratories
should evaluate the life-cycle energy and water
costs of these alternatives to calculate the payback
a
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Water Efficiency in Laboratories
period for eliminating single-pass cooling. If
air-cooled equipment is used for equipment with
high heat loads, explore options for rejecting
heat to the outside air rather than to conditioned
laboratory space (which would increase inside
temperatures and the amount of energy needed for
space cooling).
Packaged, air-cooled point-of-use chillers can also
be used for equipment cooling. Packaged chillers
work in somewhat the same way that large comfort-
load chillers do. The packaged unit recirculates
temperature-controlled fluid (i.e., refrigerant) to a
laboratory application to remove heat and maintain
a constant temperature. The recirculating fluid
picks up heat from the application and returns
it to the chiller to be cooled to a specified set
point before circulating back to the application.
Air-cooled chillers are conventionally thought to
be less energy-efficient than water-cooled chillers;
however, when considering the energy and water
use of the cooling tower system needed to support
a water-cooled chiller, this may not be the case.
Laboratory managers may want to compare the
amount of energy and water used by different
packaged chillers at both part and full loads and
select the most efficient and cost-effective model to
meet lab needs.
Chilled Water Cooling
With a chilled water cooling system, a cooling
loop provides recirculating water at a preset
temperature to cool the laboratory equipment.
Chilled water systems are closed loop, meaning
they should not lose water when operating
properly. As heat is transferred to the chilled water
loop, it must be removed by a chiller system.
Chilled water loops dedicated to cooling a single
piece of laboratory equipment are typically cooled
by an air-cooled, point-of-use chiller. Air-cooled,
point-of-use systems provide more precise control
of temperature, which is an advantage in many
laboratory operations. Larger chilled water loops
supporting multiple pieces of equipment or the
entire laboratory are cooled by central chillers that
may be air-cooled, or water-cooled using a cooling
tower. See the Cooling Towers section on page 21 in
Part II for more information on efficiently operating
a cooling tower in association with a chilled water
system.
If eliminating single-pass cooling is not possible,
consider the following best practices for single-
pass cooled equipment: use the minimum flow
rate required to cool the system recommended
by the manufacturer; or install and maintain an
automatic control system (e.g., solenoid valve) that
only permits cooling water to flow when equipment
is operating and a heat load is present. There may
also be opportunities for collecting and reusing
single-pass discharge water for other uses. This
water is typically the same quality as the incoming
water supply, so there are ample opportunities for
reuse, such as for initial rinse cycles, toilet flushing,
irrigation, and cooling tower and boiler make-up.
Water Treatment and Purification Systems
Laboratories require high-quality water for both
research and operations. The various water purity
levels (i.e., types or grades) required depend
on what the lab is used for and how it operates.
Because higher purity water is more expensive
and resource-intensive to produce, laboratories
should evaluate what grade of water is needed
to support the majority of their operations, and
design centralized treatment systems to supply that
grade. If higher-purity water is needed for certain
applications, polishers or point-of-use treatment
equipment can be used only as necessary (National
Institutes of Health [NIH], 2013).
Water treatment and purification systems within
laboratories can use a range of technologies; some
of the following technologies are often used in
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Water Efficiency in Laboratories
Microfiltration Ultrafiltration Nanofiltration Reverse Osmosis
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Figure 4. Water contaminants removed hy different levels of water treatment.
sequence to provide the desired level of water
quality:
• Microporous and carbon filtration
• Reverse osmosis and other membrane
processes
• Water softening
• Deionization
• Distillation
Sediment, Microporous, and Carbon Filtration
Sediment and microporous filtration (e,g.>
microfiltration, ultrafiltration) are common types
of water purification. Sediment filters physically
remove suspended solids greater than the filter's
rated pore size, with filters typically available that
can filter down to 1 micron. As shown in Figure
4, microfiltration can remove particles down to
0.1 micron in size, and ultrafiltration can remove
particles down to 0.01 micron. Most of the water
use comes from backwashing, which is required
when too much particulate matter builds up within
the filter. To reduce water used during filtration,
laboratories should conduct filter backwashing
as infrequently as possible and deploy pressure
sensors to determine when the pressure drop in the
filter is significant enough to warrant a backwash.
Single-use cartridge filters that do not need to be
backwashed are also available,, but they must be
disposed of after each change.
Activated carbon filtration uses adsorption to
remove chlorine and dissolved organics. Once the
adsorptive capacity of the carbon has been used up,
the filters need to either be discarded and replaced,
or regenerated offsite. While offsite regeneration
does not impact water usage within an individual
facility, laboratories are still encouraged to
regenerate only as needed.
Sediment, microporous, and carbon filtration are
commonly used in laboratories for pretreatment
prior to water undergoing additional treatment,
such as through reverse osmosis (DOE/EERE/
FEMP, 2013).
Reverse Osmosis (RO) and Other Membrane
Processes
Membrane processes filter water to remove
impurities at a smaller level than microporous
filtration. Nanofiltration can remove particles down
to 0.001 micron in size, followed by ROs (>0.0001
cfsn a
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Water Efficiency in Laboratories
micron). Nanofiltration and RO are capable of
removing more and finer particles and cations and
anions, but in return use more water during the
process.
RO is the most water-intensive membrane
process. Two streams exit an RO system: the
concentrate stream and filtered, purified water.
The concentrate is rejected water containing a
high level of dissolved minerals that is typically
sent to a drain, or a portion of it is recycled
back to the feed stream to increase the system's
overall water recovery. The recovery rate, which
is defined as the ratio of the purified water (i.e.,
permeate) volume to the total incoming water
volume, is used to represent the efficiency of the
RO system. Commercial units can typically achieve
50% to 75% recovery ratings. However, carefully
designed and optimized systems that include
appropriate pretreatment, advanced membrane
technologies, and configurations that make use of
the concentrate stream can achieve recovery rates
exceeding 90% (DOE/EERE/FEMP, 2013).
In general, higher throughput production
systems have higher recovery rates than smaller,
point-of-use systems. However, while treatment
systems with higher capacities may be more
efficient, laboratories should avoid installing
oversized systems. Oversized systems are not
only costlier, but require more space and can
lead to other inefficiencies, such as the energy
required to recirculate water within large storage
tanks. Assuming that all use points and systems
will be operated at once can lead to an oversized
system that may not provide the expected level of
performance or efficiency (Bosley, 2012).
While RO reject water includes higher levels of
contaminants than utility-supplied water, it can
often be collected and used within other systems
or processes. See the Alternative Water Sources
section on page 32 for more information.
Water Treatment Efficiency Principles
To summarize, major water-saving principles for
water treatment systems include:
• Identify the minimum quality of water
required for laboratory research and
operations and use treated water only when
necessary.
• Avoid over sizing treatment systems.
Consider use of point-of-use treatment
systems where highly purified water use is
limited.
• Backwash filters based on pressure drop and
regenerate carbon, ion, and resin beds only
when necessary (e.g., based on volume of
water treated or conductivity readings) rather
than on a set schedule.
• When purchasing new RO or membrane-
based treatment systems, select systems
with higher recovery ratings and look
into optimizing system design to achieve
efficiency.
• Explore opportunities for reject water to be
reused for other processes.
Water Softening
Laboratories often use water softeners to generate
boiler feed water and to otherwise pretreat water
prior to additional forms of purification. Cation
exchange is a common method for softening
water, as the process replaces calcium and
magnesium ions with sodium ions. As the sodium
ions get used up, the water softening beds need
to be regenerated by backwashing with a brine
solution. Regeneration can cause excess water
use in ion exchange systems, but unlike activated
carbon filters, this regeneration typically happens
onsite and therefore impacts a lab's overall water
use. Laboratories should select demand-initiated
water softeners, meaning that regeneration occurs
based on incoming water's hardness, the volume
of water softened, or treated water conductivity
rather than on a set schedule (EPA).
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Water Efficiency in Laboratories
Beyond how regeneration is initiated, important
considerations for selecting a water softener
include a system's water consumption during
regeneration and its salt efficiency. With respect
to water consumption, look for systems that
use 4 gallons of water or less per 1,000 grains of
hardness removed. For salt efficiency, look for
systems that can achieve at least 3,500 grains of
hardness per pound of salt (ASHRAE and ICG,
2020).
Deionization (DI)
DI is a treatment process commonly used in
laboratories that is similar to water softening.
Water is sent through resin beds of cations and
anions, which bind to the ions in the water supply
to provide deionization. Similar to activated
carbon filters, resin beds have a limited binding
capacity and must be regenerated periodically to
ensure effectiveness (NIH, 2013). Regeneration
typically occurs offsite and therefore does not
impact facility-level water use (EPA).
Distillation
Distillation separates water from impurities by
heating water to vapor and condensing it back
into a liquid in a separate vessel. Smaller units
are often more water-efficient, as they can have
no discharge, whereas larger stills reject about
15% to 25% of water that enters the system.
However, a major source of water use that may
occur during distillation is through condenser
cooling. Some labs still use single-pass cooling
water for this purpose, which can use a substantial
amount of water during the distillation process.
Replacing distillation equipment that uses single-
pass cooling with air-cooled models or using
recirculating chilled water to provide condenser
Autoclave Awareness Helps Contribute to Long-Term Water Savings
Education, outreach, and researcher awareness are critical components of a successful laboratory water
efficiency program. Signage, email reminders, and staff incentives can help catch leaks or other water waste.
Water savings kits made up of a solenoid valve reduce the amount of water consumed in older autoclave
models. These solenoid valves can eliminate the continuous flow of water used for condensate tempering.
Once the valve is installed, tempering water is only applied when the autoclave is operational and cooling is
required. However, these kits have a lifespan of 5 to 7 years, much shorter than the lifespan of the autoclave
itself. When these kits fail, they fail open, thus allowing the constant flow of cold water to pour down the
drain. At 3.0 gpm, that's more than 1.5 million gallons per year! Because
autoclave users aren't necessarily responsible for maintaining the
equipment, it is unlikely that a failed solenoid valve is discovered and
replaced in a timely manner.
All lab autoclave users should be trained in identifying what a failed
valve sounds like and understand the need to report it immediately. For
example, the University of Georgia (TJGA) placed awareness stickers on
every campus autoclave to ensure users are aware of the valves and can
identify what a failed valve sounds like. In the first week the stickers
were placed, two units with failed valves were identified by users,
saving TJGA up to $48,000 in annual water and sewer costs. TJGA
conducted education and outreach on the program, replaced failed
solenoid valves for free, and engaged with manufacturers and service
vendors to bring awareness to these water savings efforts.
[DIDYOU KNOW?!
A FAILED SOLENOID VALVE IN AN AUTOCLAVE COULD
WASTE 2.6 MILLION GALLONS OF WATER A YEAR!
IF YOU NOTICE A GURGLING SOUND NEARTHE DRAIN
OF THIS AUTOCLAVE BETWEEN CYCLES,
PLEASE NOTIFY THE UGA GREEN LAB PROGRAM AT
GREENLAB@UGA.EDU OR 706-542-7884.
THANKY0U!
Example signage posted by the UGA Green
Labs program. Source: Star Scott, Green Lab
Program Coordinator at UGA
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cooling can save water. More information on
alternatives to single-pass cooling can be found in
the Equipment Cooling section on page 6.
Steam Sterilization
Steam sterilizers (sometimes referred to
as autoclaves) are used for disinfection in
laboratories. Table-top units are typically small
and do not use significant amounts of water.
However, larger stand-alone sterilizer models
can use a substantial volume of water to produce
steam and to cool wastewater before discharge.
Some sterilizers also use water to create a vacuum
to expedite drying, either through a venturi-based
water-ejector or a liquid ring vacuum pump.
In older steam sterilizer models, the majority
of water use results from condensate cooling.
Prior to being discharged to a sanitary sewer,
condensed steam from the sterilizer must be
cooled to 140°F (60°C) or less. This is done by
adding cold water (typically from the main water
supply) to the condensate to temper it before
discharges, as much as 1 to 3 gallons per minute.
Many older models apply tempering water
continuously, even when the equipment is idle or
turned off and does not require the same level of
condensate cooling.
In general, newer steam sterilizers are designed
to apply cooling water only when necessary.
These models include a cooling reservoir to
assist with condensate cooling prior to discharge
and/or a temperature-actuated valve to only
apply tempering water when the condensate
discharge is above 140°F. Older models without
these features incorporated into their design
can be retrofitted with a water savings kit that
includes a solenoid valve. These retrofits can
reduce condensate cooling water use by up to
90% (Koeller et al„ 2004). Another solution that
can eliminate once-through tempering water is
to provide condensate cooling through a heat
exchanger connected to a building chilled water
loop (Consolidated Sterilizer Systems, 2021).
Newer, stand-alone sterilizers commonly include
their own boiler system that can capture and reuse
the condensate from within the sterilizer, saving
both energy and water.
Steam sterilizers can also be designed or
retrofitted with a water recirculation system to
reduce the amount of water necessary to draw
a vacuum through the sterilization chamber. In
a conventional steam sterilizer, the vacuum is
generated by passing water at a high velocity
through an ejector at a flow rate of 5.0 to 15.0
gallons per minute (gpm) and discharging it
directly to the sanitary sewer (Koeller, 2004). A
recirculation system can be used to capture and
reuse some of the water. Some newer steam
sterilizer models offer an electric liquid-ring
vacuum pump or a dry vacuum that can reduce
water used to establish a vacuum significantly. Dry
vacuum systems should be selected for all new
equipment.
Following are ideas for reducing water use from
steam sterilizers:
• Turn off the steam sterilizer when not in use
or program the sterilizer to turn off at the
end of the workday, on weekends, or after
being idle for an extended period.
• Retrofit older steam sterilizer models to
include a temperature-actuated valve and/
or cooling tank to reduce the frequency that
tempering water is applied, particularly
during periods when equipment is idle.
• Periodically inspect temperature-actuated
valves to make sure they are functioning
properly and that tempering water is only
being applied while the steam sterilizer is
operating.
• Identify alternative sources of cooling water,
such as RO system reject water, that may be
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Water Efficiency in Laboratories
vacuum systems are more energy-efficient and
eliminate the use of water, reducing long-term
operating costs. As with water treatment
systems, centralized vacuum systems can often
be oversized. If vacuum needs can be supported
by smaller, point-of-use electric-powered vacuum
pumps rather than a larger, centralized system,
a lab can save significant amounts of energy and
water.
available in the lab that can be collected for
use as tempering water (Stanford University,
2013).
• Consider installing a system to recover and
recirculate water used to create the vacuum.
• Select sterilizer models that use a dry
vacuum system rather than a water-ejector
or liquid ring vacuum pump.
• Consider sterilizer models that include a
stand-alone boiler system that recovers its
condensate.
• Replace older units with newer models that
are designed to reduce energy and water
use through the technologies described
above.
Vacuum Systems
Laboratories use vacuum systems to collect
waste gases, liquids, or debris from a vessel or
enclosure. Historically, "wet" vacuums pumps
(which use water to create the vacuum) have been
used. There are two types of wet vacuum pumps:
liquid ring and aspirator (i.e., venturi) vacuum
systems; aspirators in particular waste large
amounts of water. Liquid ring vacuum pumps
use water to form a vacuum seal, which gathers
impurities. The seal and cooling water needs to be
discharged and replenished with fresh water to
remove impurities and heat. Water requirements
for wet vacuum systems range from 0.5 to 1.0 gpm
per horsepower (EBMUD, 2008). Water can also
be used to cool dry vacuum systems. If water is
being used for cooling of either wet or dry vacuum
systems, consider connecting the vacuum system
to a recirculating water loop.
Where feasible, replace existing wet or water-
cooled vacuum systems with dry, air-cooled
models. Aside from use in explosive or extremely
corrosive environments, dry vacuums can be
used in most laboratory settings. While they can
be more expensive to procure, these newer dry
Other tips for saving water in vacuum systems
include:
• Turn off the vacuum pump when not in use.
• Ensure the vacuum pump is operating
according to the manufacturer's
specifications with respect to seal and
cooling water.
• Consider installing a system to recover and
recirculate seal and cooling water, which can
reduce water use by 50% to 80%.
• Replace older, wet or water-cooled vacuum
systems with dry, air-cooled models to
improve both energy and water efficiency.
Glassware Washers
Glassware washers are used to remove chemicals
and other material from laboratory glassware. A
common misconception is that glassware washers
use more water than hand washing, but in reality,
glassware washers are much more efficient and
effective. Laboratory glassware washers are often
supplied with potable water as well as purified
(e.g., DI or RO) water. In these instances, potable
water is used for initial pre-rinse and washing
stages, whereas purified water is used in the final
rinse stage to make sure no residual contaminants
or minerals are left on the glassware.
Newer glassware washers use less water than
older models, as they include flow control and
sensing capabilities. With newer models, the
operator can also select the number of rinse
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Water Efficiency in Laboratories
Glassware washer image courtesy of Lahconco Corporation.
cycles. Fewer cycles should be selected whenever
possible, as long as this would not affect the
laboratory's desired level of cleanliness. Because
water used in glassware washers is typically
heated to high temperatures, operating more
water efficiently will save energy too.
When purchasing new glassware washers, choose
a size (e.g., undercounter, free-standing) that fits
the needs of the laboratory without oversizing.
Compare similar models based on water and
energy use and select more efficient models.
Consider add-ons like ''cool-down" tanks, water
recycling systems, or heat recovery systems that
can reduce water and/or energy use.
Vivarium Systems
Vivaria use specialized equipment related to the
care and housing of animals such as cage, rack,
and bottle washers and animal watering systems.
Cage, Rack, and Bottle Washers
All vivaria must wash cages, racks, bottles, and
other items used for the care and feeding of
animals. There are two basic types of systems
for washing cages: batch-type washers and
continuous tunnel washers. Hot water use from
cage, rack, and bottle washing is also a major
contributor to laboratory energy use.
Batch-type cage, rack, and bottle washers function
similarly to a residential dishwasher. Cages, racks,
and/or bottles are loaded into the washer, which
then completes a wash cycle. Cleaned equipment
is then removed and prepped to be used again
for animal care. Batch-type washers include
multiple cycles (i.e., pre-rinse, wash, final rinse),
although additional cycles may be selected for
more specialized cleaning requirements. Each
additional cycle increases water used per batch.
Newer washers use between 12 and 50 gallons of
water per cycle (up to 150 gallons per load for a
conventional three-cycle wash); however, older
units can use nearly 500 gallons per load (EPA).
'funnel washers are typically found in laboratories
that require large amounts of cage and rack
washing. Tunnel washers use a conveyor system,
with staff stationed at each end to feed dirty cages
and racks and remove them once cfean. Tunnel
washers use a counter-current washing process,
meaning water used for each subsequent rinse
cycle is recyCied within the previous cycle (i.e., the
cfeanest water is only needed for the finai rinse
phase; water for eariy rinsing tasks, when the
quafity of water is not as important, is recycied
from later in the process). Tunnel washers typically
vent into: the workspace continuously during
operation, which results in higher air conditioning
requirements.
Comparing these two washer options, one study
found that batch-type cage and rack washer
operations were more water- and energy-efficient
and couid result in fewer hours of labor to operate.
For the same throughput, the study found tunnel
washers would use, on average, 21% more water
and 69% more steam, although would use 11%
less electricity (Zynda, 2015).
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WaterSense
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Water Efficiency in Laboratories
Various types of water (e.g., softened, RO/DI,
heated) can be used for washing, depending on
each laboratory's specific needs. High-quality,
treated water should only be used if necessary.
See the Water Treatment and Purification Systems
section on page 7 for more information on
efficiently operating these systems. If hot water
greater than 140°F is used, tempering water
might also be used to cool water prior to sewer
discharge.
Reducing water use within cage, rack, and
bottle washing operations can also result in
commensurate energy and chemical savings. To
summarize, major water saving principles for
cage, rack, and bottle washers include:
• Wash only full loads for batch washers and
schedule wash runs for tunnel washers to
maximize the equipment washed during
each run.
• Use high-quality water only for the final
rinse cycle.
• Choose the minimum number of wash and
rinse cycles necessary to effectively clean
equipment.
• Minimize or eliminate tempering water
use by installing a heat exchanger to cool
washer effluent prior to discharge.
• When purchasing new washers:
~ Consider batch-type washers over
tunnel washers to reduce utility costs
and labor requirements;
~ Avoid oversizing equipment;
~ Select models that use less water per
cycle;
~ Select models that allow users to
specify the number of rinse cycles;
and
~ Choose equipment capable of
recycling final rinse water for the first
wash.
Animal Watering Systems
Automatic watering systems supply drinking
water to animals within laboratory settings.
Although these systems are a less labor-intensive
alternative to manual bottle filling, they can result
in greater water use. Systems should be selected
and operated with the primary goal of providing
adequate volumes of water for animal care while
preventing transmission of pathogens or other
bacterial buildup; however, water efficiency should
also be considered.
Animal water systems can be either flushing
or recirculating systems. Flushing systems use
either a continuous or periodic water flow to
maintain water quality and flush watering piping
and bottles, but then it goes right down the drain
to the sewer system. Recirculating systems use
a constant flow of recirculating water flow that
is treated using ultraviolet or other methods of
disinfection, and are much more water-efficient.
If the water supplied to your lab's animal watering
systems requires pretreatment, make sure to
optimize system efficiency. Eliminate continuously
flushing systems and automate flushing systems
to reduce the occurrence of flush cycles to only
when water quality considerations dictate.
Before purchasing new or replacing automatic
animal watering systems, consider whether
manually filling water bottles is feasible. If your
laboratory decides to move forward with an
automatic system, consider selecting one that is
recirculating, provided the necessary disinfection
can be provided in a cost-effective manner.
See the Water Treatment and Purification Systems
section on page 7 for more information.
Laboratory Fume Hoods
Most fume hoods—which contain and remove
harmful air from the lab—simply exhaust the
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Water Efficiency in Laboratories
"Shut the Sash" Efforts Contribute to Water
Efficiency
fumes through duct work to the outside. For
low concentrations of hazardous substances,
filtered fume hoods may eliminate the need for
exhaust completely. These filtration systems use
inert adsorbents (e.g., activated carbon, activated
alumina) or chemically active adsorbents (e.g.,
potassium permanganate). These dry filtration
systems effectively contain and trap low
concentrations of contaminants. Owners must
make sure to replace adsorbent as indicated by
sensors or time logs.
A few laboratory operations (e.g., those involving
acid fumes, toxic materials, and perchlorate)
require hoods that remove contaminants through
special treatment prior to the air being exhausted
to the atmosphere. They require wet scrubbers
or special wash-down equipment to remove
potentially combustible products.
Wet Scrubbers
Within wet scrubbers, contaminated air from
the fume hood passes through a spray or wetted
packed column, where it comes in contact with
water (and sometimes additional scrubber
reagents), which absorbs water-soluble gases,
vapors, aerosols, and particulates. The scrubbing
liquid should be recirculated back though the
scrubber with monitoring for saturation by
the contaminants. A portion of the liquid will
eventually need to be discharged (blown down)
to control total dissolved solids and other
contaminants, and make-up water is added to
maintain scrubber circulating water quality. Mist
eliminators installed in the discharge from the
scrubber both prevent the release of the scrubber
fluid and save water.
Other water-saving suggestions for fume hood
scrubbers include:
"Shut the Sash" campaigns, which encourage
researchers to close the window (or "sash") on
laboratory fume hoods to promote safety and
energy savings, can contribute to water efficiency
too. Reducing the amount of conditioned air
needed within a laboratory will reduce the load
on a cooling tower, therefore reducing the tower's
water consumption. For labs that use a wet
scrubber system on fume hoods, eliminating
unnecessary air flow through the fume hood will
also reduce evaporation that occurs from the wet
scrubber.
The sash of a laboratory fume hood typically only
needs to be open during experiment set up and
active use by a researcher. The energy savings
and safety benefits of "Shut the Sash" campaigns
are well documented. These campaigns can
include different strategies for educating
researchers on the importance of shutting the
sash, including:
• Intuitive and compelling (e.g., colorful)
stickers indicating the sash height that
provides the most safety and uses the least
energy (see right).
• Educational signage, emails, webpages, and
informational materials about the safety and
energy benefits.
• Periodic compliance evaluations and
feedback to researchers and lab managers.
• Periodic competitions and/or rewards.
Energy reductions from "shut the sash"
campaigns stem from reducing the air flow
through variable air volume (VAV) fume hood
systems. When a sash is shut on a VAV fume hood
system, the HVAC system doesn't have to work as
hard because it's removing less air, thus reducing
the amount of conditioned air needed to replace
it. (FEMP, 2012b; Aldred Cheek and Wells, 2020).
Image courtesy of University of California, Davis.
KEEP SASH
AT OR BELOW
THIS LEVEL
V
ALWAYS CLOSE
NOT WORKING
IN HOOD.
,*>... 4 15 on
WaterSense
-------
Water Efficiency in Laboratories
• Turn off water flow when systems are not in
use.
• When a hood must be in continuous
operation, but no actual work is occurring,
encourage lab users to close the fume hood's
sash (see sidebar on page 15). This reduces
evaporation in the wet scrubber and reduces
air loss from the heated or cooled laboratory
space.
• Use water (scrubber fluid) recirculating
systems.
• Make sure liquid level controllers and water
make-up valves are functioning properly.
• Control blowdown based on scrubber fluid
chemistry, rather than allowing continuous
blowdown or based on a timer.
• Minimize air flow through the wet
scrubbers. Reducing the amount of air
passing through the scrubbers will reduce
evaporation.
• Size equipment to the task and install mist
and drift eliminators.
Perchlorate or Perchloric Acid Wash-Down
Systems
Perchlorate or perchloric acid wash-down
systems are a specialty type of fume hood used
for these unstable, explosive compounds that
tend to deposit on hood and ductwork surfaces.
Wash-down systems are used to periodically wash
these substances from the surface of the fume
hood and associated ducts. Water is sprayed onto
the hood and ductwork surfaces, then it is drained
to the sewer. Fume hood systems and ducts
should be designed to minimize surface area, and
thus the amount of water needed. This ductwork
should be designed to take the shortest path to the
outside and remain separate from other ductwork.
This both reduces the surface area that needs to be
washed (thus saving water) and avoids perchlorate
from coming into contact with organic fumes
and other combustible substances. Applicable
regulatory guidance can be found in ANSI/AIHA/
ASSP Z9.5 -Laboratory Ventilation and NFPA
45 Standard on Fire Protection for Laboratories
Using Chemicals.
Water-saving principles for perchlorate hoods
include:
• Avoid using continuous washers or retrofit
them to include automatic shutoff valves
when the hoods are not in use.
• Establish operating procedures to schedule
wash-downs when necessary to ensure
health and safety; however, reducing the
runtimes of this equipment will save water.
• Work with the equipment supplier to
design an efficient system and operating
procedures.
Humidifiers
Humidification of the laboratory working space is
often necessary, especially in colder climates, to
maintain proper humidity, both for researchers'
comfort and to control the growth of harmful
organisms such as mold, viruses, bacteria, and
mites. Most laboratories try to keep relative
humidity between 40% and 60 % and require
significant fresh air turnover rates. Two basic types
of humidification processes are used in labs:
• Isothermal systems use an internal or
external heat source to boil water, which is
injected as steam or water vapor directly
into the circulating air.
• Adiabatic systems either spray water into
the air space (atomizers) or otherwise use
the air in the room to evaporate water with
the aid of wetted media or mechanical
energy.
Table 1 on page 17 includes different humidifier
types, as identified by the ASHRAE Handbook-
HVAC Systems and Equipment (ASHRAE, 2020).
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Water Efficiency in Laboratories
Table 1. Types of Humidifiers
Isothermal
Adiabatic
Hot water heat exchanger
Centrifugal atomizer
Steam heat exchanger
Compressed air atomizer
Direct-injection steam
Pressurized-water
atomizer
Electric infrared steam
Ultrasonic atomizer
Electric resistance steam
Hybrid spray/media
Electrode steam
Wetted media
Gas-fired steam
By design, humidifiers consume water to add
moisture to conditioned air. However, additional
water use can occur from either 1) blowdown or
discharge to prevent a buildup of minerals in the
system; or 2) treatment of the humidifier water
supply Blowdown is required in humidifiers to
periodically control the levels of total dissolved
solids (IDS) and minerals in the system. The only
exception to the need for blowdown is an atomizer
system that sprays treated water directly into the
air. Direct steam injection systems obtain steam
from a central boiler system, and therefore do
not require additional treatment or blowdown at
the point of use, but blowdown and treatment are
required at the central boiler.
Very pure water produced by reverse osmosis
or deionization is recommended for many types
of humidifiers. In particular, atomizers typically
require purified water in many laboratories,
since tap water contains minerals and other
contaminants that would be sprayed into the
indoor air. Also, wetted media, ultrasonic,
centrifugal, and hybrid spray systems need the
water in them to be controlled for bacteriological
growth through the addition of biocides, even
when high purity water is used. When operating
humidifiers or selecting new equipment,
laboratories should examine the water that
is required for blowdown, as well as waste
generated through generation of BO or other
treated water.
Energy efficiency is also a consideration when
selecting or operating humidifiers. Isothermal
humidification requires the generation of steam or
hot water, which can be energy-intensive. Since
centralized boiler systems are usually operated
more efficiently than stand-alone steam boiler
humidification systems, direct steam injection
tends to be both more energy- and water-efficient.
However, laboratories should evaluate steam
quality to make sure it is suitable for direct
injection and will not negatively impact air quality.
Adiabatic systems require the evaporation of
water, which has a cooling effect on the air in the
space being humidified. This is beneficial in warm,
dry climates where cooling is needed in addition
to humidification. In colder climates, or in winter,
adiabatic systems may not be suitable, and more
energy will be required for space heating.
Labs requiring special humidification should
be isolated from other labs and non-lab areas
with walls, vapor barriers, and sealed doors.
Labs with very intensive humidification or tight
humidity control may require airlock vestibules
to maintain proper control. Lab humidification
operations should be properly controlled with
instrumentation to measure relative humidity and
keep typical levels between 40% and 60%. This
ensures that only the water and energy needed
to control humidity is used and comfortable, safe
conditions are maintained. Often, however, lab
areas requiring relative humidity levels above
30% are limited and can be humidified by local
trim humidifiers. Therefore, the energy and
water consumption of central humidification of
the ventilation system for the overall facility can
be decreased by maintaining a lower minimum
relative humidity setpoint elsewhere in the
facility (e.g., 25% or 30%). For older lab buildings
located in cold climates, it is sometimes necessary
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Water Efficiency in Laboratories
to decrease the humidity levels when outdoor
temperatures decrease to reduce condensation
on windows, window frames, and walls and mold
forming inside the lab from condensing moisture.
Labs should carefully choose humidifier
equipment and make sure it is sized for the type
of laboratory and operating conditions where it is
being installed. Work with a qualified vendor to
select equipment and controls designed for energy
and water efficiency.
Photographic and X-Ray Equipment
Photographic and X-ray machines in laboratories
may require water for film processing or
equipment cooling. Many laboratories have
switched to digital equipment to eliminate water
and chemical use, improve image quality, and
generally improve operational efficiency and
safety. Put simply, if laboratories are still using
traditional film processing equipment, it may be
time for a digital upgrade!
Laboratory Design
Initial laboratory design presents a clear
opportunity for incorporating water efficiency.
Early in the planning and design process,
designers should consider opportunities for
minimizing water use and incorporate alternative
water sources.
Water Mapping and Concept/Schematic Design
As the project team is establishing sustainable
design goals and conceiving strategies to achieve
them, this is the best time to begin to develop a
water mapping study. In new facilities, a water
mapping study can help designers plan water
system configurations; identify synergies for
simultaneous demands and sources; reserve
The earliest stages of design have
the greatest potential to meaningfully
reduce the water use intensity of a
laboratory.
space for equipment; and identify opportunities
for greater efficiency. Water mapping, an example
of which is shown in Figure 5 on the next page,
compares all available sources of water (e.g.,
potable water, reclaimed water, graywater) to
water end uses, based largely on availability
and water quality needs. Water mapping can
assist designers in identifying opportunities for
efficiency and water reuse so they can be designed
in from the onset.
To complete water mapping, first develop
building systems concepts for major water end
uses, including: potable water (e.g., drinking,
handwashing, showers); sanitary fixtures (e.g.,
toilets); scientific processes (e.g., humidification,
RO/DI); site maintenance (e.g., irrigation); and
HVAC systems (e.g., cooling towers, steam
boilers). Consider system alternatives that reduce
overall water use. Focus particularly on building
heating and cooling system options and their
overall water use profile. For example, air-source/
ground-source heat pumps with heat recovery
may be alternatives to cooling towers. Consider
the interaction of energy and water demands with
HVAC system selection.
Next, identify alternative water source options,
including rainwater capture, HVAC condensate
recovery, RO reject, other graywater collection, or
reclaimed water. Locate potential water storage
areas for cisterns or tanks to collect alternative
water. Ideally, storage locations would be in close
proximity to the proposed end use(s). Finally,
determine if alternative water sources are of
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Water Efficiency in Laboratories
I
Demand
I
Discharge
Municipal Water
Site Stormwater
Municipal
Storm System
Figure 5. Example water map developed for a typical laboratory. Figure courtesy of Vanderweil Engineers.
sufficient water quality to serve any proposed
end uses and/or examine whether water quality
must be improved by installing water treatment
equipment.
Cost and budget are primary concerns, so project
teams should establish budget parameters for
potential water efficiency upgrades or alternative
water sourcing. Water efficiency or alternative
water projects should be evaluated on a lifecycle
basis, taking into consideration the per-unit
cost of water and sewer service, operations and
maintenance costs, and potential energy use or
savings. For example, energy recovery strategies
that reduce energy consumption may also reduce
the demand for water at the cooling tower, so
both energy and water cost savings should be
quantified.
Design Development
The design development phase is an opportunity
to further refine water-saving design options that
meet project goals and fit within the budget. The
design team can begin to select water-efficient
equipment, plumbing fixtures, and irrigation
equipment (if applicable); optimize the size of
cisterns for alternative water storage; develop
more accurate water calculations; and detail the
plumbing riser diagrams showing the network
of water demands and sources. As the energy
model for the project becomes more detailed and
representative of the proposed design, extract
the cooling loads on the chilled water system or
cooling tower to estimate cooling tower make-up
more accurately throughout the year and optimize
the capacity of heat recovery equipment.
The monthly patterns of water sources and
demands may not align, therefore requiring
creativity by the design team to assess water loads
throughout the year. For example, cooling tower
and irrigation loads peak in the summer, but can
be much smaller or negligible during the winter.
A building that utilizes rainwater or year-round
sources (e.g., RO reject) may need to align those
A
19
Water Sense
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Water Efficiency in Laboratories
winter sources with year-round demands such as
toilet flushing. Otherwise, reclaimed water in the
winter months may need to be wasted.
Design development is the phase during which
scientific equipment requiring cooling should
be specified. Design teams should evaluate the
lifecycle costs of air-cooled versus water-cooled
models, looking carefully at the energy and water
needed to operate these systems. If water-cooled
systems are used, design teams should investigate
opportunities to recapture waste heat for use in
the building heating loop via the heat recovery
heat pump, thus reducing the evaporation of
potable water at the cooling tower.
As plumbing piping main distribution is planned
throughout the facility, designers should minimize
the length of branch piping between the hot
water recirculation loop and hot water outlets at
showers and lavatories to reduce the amount of
water wasted and length of time to receive hot
water. The plumbing design should reduce the size
of the branch piping as much as possible within
code requirements to further reduce the volume
of cooled water between the hot water loop and
outlet.
Construction Documents and Construction Phase
As the design team completes the construction
documents, this is an opportunity to further refine
the design of water savings strategies through
submetering, detailed sequences of operation, and
specification of water-saving equipment.
Water meters and submeters should be connected
to a building automation system (BAS) or other
systems used to monitor and report utility
consumption. Meter data should be recorded
in volume units rather than instantaneous flow;
recorded at regular intervals, ideally hourly or
every 15 minutes; and stored digitally for at least
3 years. Meters connected to a monitoring-based
commissioning (MBGx) system, sometimes
referred to as a fault detection and diagnostics
(FDD) system, can be used to more quickly identify
anomalies in water usage. This can speed up
troubleshooting of leaks and other operational
problems that result in water waste.
Sequences of operation for alternative water
systems and water filtration systems should be
detailed on contract documents, including the
locations of meters, sensors, and equipment.
Design teams should consider how to prioritize
where alternative water is directed, and when
to utilize backup potable water sources. It's also
important to ensure that heat recovery systems
balance energy and emissions reductions with
potential water savings, particularly with the
operation of heat recovery heat pumps.
During the construction and turnover process, an
independent commissioning agent should perform
functional testing on plumbing and mechanical
systems to ensure that they are operating as
intended by the design team, and to facilitate
training of the owner's facility staff to maintain
these systems in working order.
Occupancy
The most well-intentioned water saving design
means little without producing measurable water
savings. Lab operators should monitor water
consumption relative to estimates by the design
team. While some variability is expected through
different seasonal and daily patterns, monitoring
water consumption can reveal when significant
issues arise, such as too-frequent cooling
tower blowdown, a significant water leak, or a
malfunctioning alternative water system.
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Water Efficiency in Laboratories
PART II: WATER SAVINGS OPPORTUNITIES
NOT SPECIFIC TO LABS
Beyond lab-specific equipment, there are many
opportunities for water savings within the
plumbing and mechanical systems and equipment
commonly found in other commercial building
types. In fact, because laboratories typically
have high demand for heating and cooling,
savings opportunities may be more significant
than in other building types. Further, due to the
interdependency of energy and water use within
facilities (particularly with respect to cooling
towers and steam boilers), energy and water
efficiency efforts go hand-in-hand. In effect, efforts
made to reduce energy demand, process and
heat loads, and the use of steam can contribute to
laboratory water savings as well.
Cooling Towers
Cooling towers might represent the largest single
opportunity for lab water efficiency. Even lab
facilities that receive chilled water from central
campus chilled water systems indirectly consume
large quantities of water for that cooling at the
campus plant cooling towers. Laboratories
usually have significant comfort-cooling and
process loads. They often use 100% outside air
for ventilation, making their comfort cooling
loads much higher than those of typical office
buildings. Additional cooling is often needed for
special equipment such as lasers and electron
microscopes. Nearly 50% or more of all the water
used in multipurpose laboratories can be for
cooling (EPA).
Cooling towers use evaporation to dissipate
heat from recirculating water used to cool
chillers and other process equipment. By design,
condenser water systems and cooling towers
help water-cooled lab process equipment be
more water-efficient, since water can continue to
Drift
V | » ' J J Evaporation
Fan Deck -—-—
Water sprayed —
downward
1 u
A A A A A/
1
\ t Air f Air f /
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Heat
exchanger
Pump
^ v i
T
Make-up
Water with concentrated
J
water
Dissolved solids m
' Cool water
I
Blowdown
Figure 6. Typical water flow within a cooling tower system.
Figure courtesy of the Federal Energy Management
Program.
be recirculated to meet cooling demand rather
than being used once and sent down the drain.
However, careful management of the cooling
tower system is needed to ensure this efficiency is
maximized.
Cooling towers use water in three ways:
evaporation, blowdown (i.e., bleed-off), and
drift. Figure 6 above illustrates water use in a
typical cooling tower. Malfunctioning towers
may also lose water through overflow and leaks.
Evaporation is the primary function of the cooling
tower, and opportunities to reduce evaporation
focus mostly on strategies that reduce the
cooling load on the cooling tower rather than
modifications to the tower itself. The quantity of
water evaporated is fixed—approximately 1.80
to 1.85 gallons of water are evaporated for every
ton-hour of cooling. This includes the ton of heat
removed from the facility (one ton-hour = 12,000
British thermal units [BTUs]) as well as the heat
from the compressor, air handling units, and
pumps used to operate the cooling system. Given
this, anything a laboratory can do to improve
energy efficiency and reduce the cooling load of
the building and equipment supported by the
cooling tower will have a commensurate reduction
in water consumption from evaporation.
A
21
Water Sense
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Water Efficiency in Laboratories
When water evaporates from the cooling tower,
dissolved solids (e.g., calcium, magnesium,
chloride, silica) are left behind in increasing
concentrations.
To control the concentration of
dissolved solids, cooling towers blow
down a portion of the recirculating
water and replace it with make-up
water with a lower concentration of
dissolved solids.
Blowdown is the primary target of cooling tower
water efficiency management efforts once loads on
the cooling tower have been optimized.
Cooling towers lose some water through drift and
leaks or overflow. Drift, the loss of unevaporated
water into the atmosphere, can be controlled by
drift eliminators. High-efficiency drift eliminators
can be installed or retrofitted onto cooling towers
to reduce drift losses to 0.005% or less of the
recirculating water flow.
Lastly, while leaks and overflow are not intended
by design, cooling tower fill valves can
malfunction and should be monitored regularly.
Consider retrofitting existing towers with an
alarm or sensor that communicates when water is
detected in the cooling tower's overflow drain.
Make-up water, which represents the overall
consumption of the tower, is the sum of water lost
through evaporation, blowdown, drift, leaks, and
overflow.
Cooling Tower Water Management
The primary methods for managing water use in
cooling towers are operational. To improve the
tower's water efficiency, the goal is to increase the
cycles of concentration (CoC) to the maximum
extent possible without overly concentrating
dissolved solids or other constituents in the water,
4-° 3.60
2 2.5 3 3.5 4 4.5 5 6 8 1 0 1 5
Cycles of Concentration
Make-up A Blowdown )( Evaporation
Figure /. Cooling tower water use per ton-hour of cooling (gallons)
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Water Efficiency in Laboratories
Table 2. Percent of Cooling Tower Make-Up Water Saved by Maximizing Cycles of Concentration
New Cooling Tower CoC
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
33%
44%
50%
53%
56%
58%
60%
61%
62%
63%
64%
—
17%
25%
30%
33%
38%
40%
42%
43%
44%
45%
—
—
10%
16%
20%
25%
28%
30%
31%
33%
34%
—
—
—
7%
11%
17%
20%
22%
24%
25%
26%
—
—
—
—
5%
11%
14%
17%
18%
20%
21%
—
—
—
—
—
6%
10%
13%
14%
16%
17%
—
—
—
—
—
—
4%
7%
9%
10%
11%
—
—
—
—
—
—
—
3%
5%
6%
7%
Table 3. Cooling Tower Maximum Recirculating Water Properties From ASHRAE 189.1
(ASHRAE and ICC, 2020)
Recirculating Water Parameters
;imum Value
Conductivity (micro-ohms)
3,300
Total dissolved solids (ppm)
2,050
Total alkalinity as CaC03 (ppm) excluding galvanized steel
600
Total alkalinity as CaC03 (ppm) galvanized steel (passivated)
500
Calcium hardness as CaC03 (ppm)
600
Chlorides as CI (ppm)
300
Sulfates (ppm)
250
Silica (ppm)
150
Langelier Saturation Index (LSI)
+2.8
which can lead to scale, corrosion, or biofouling.
GoG is an indication of how many times water
recirculates in the tower before blowdown occurs
Therefore, increasing the GoG of the tower
reduces the consumption of make-up water and
results in greater water efficiency. Figure 7 on
page 22 and Table 2 above show the effect of the
GoG on make-up water use. Note that increasing
the GoG from two to six yields nearly 90% of the
savings that can be obtained by increasing the
cycles from two to 10. Targeting at least six cycles
is therefore a good goal.
Figure 7 on page 22 includes the water required
to provide one ton-hour (15,000 BTU) of cooling.
For reference, one ton of building cooling is
equivalent to 12,000 BTU/hour, but cooling towers
require more energy per ton of cooling because
the mechanical compressors in chillers and heat
pumps also generate heat that must be dissipated.
Perhaps the best way to increase a tower's GoG
is through better monitoring and management of
the water chemistry. The first step is to understand
the quality of the incoming water and what
the controlling parameter should be, such as
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Water Efficiency in Laboratories
Understanding Cycles of Concentration
Since CqC represents the relationship between the
concentration of dissolved solids in the blowdown
to the concentration in the make-up water, it can be
expressed as.-
CoC=
Conductivity of Blowdown
Conductivity of Make-Up Water
If a cooling tower is metered for make-up and
blowdown, CoG can be calculated based on the
volume of make-up and the volume1 of blowdown.
me
Make-Up Volume
Blowdown Volume
The amount of water that can be saved by increasing
CoC can be calculated as:
(CoCl-CoC2)
Savings = Initial Make-Up Volume * —
CoCl*(CoC2 -1)
Where CoCl is the initial cycles and CoC2 is the
target cycles of concentration.
hardness, silica, or TDS. ASHRAE 189.1 Standard
for the Design of High-Performing Green
Buildings provides guidance on the maximum
value of certain recirculating water parameters,
shown in Table 3 on page 23, Towers made
using Type 316 stainless steel or other materials
that protect against Corrosion may be able to
operate under higher parameters than indicated
in Table 3. Laboratories should Consult with a
qualified treatment vendor and/or the cooling
tower manufacturer to understand recommended
parameters for their specific tower and water
chemistry.
Without additional forms of treatment,
the maximum CoC for Cooling towers is
largely dependent on make-up water quality.
Understanding this relationship can help to
4000
3500
>»
3000
>
Xj
2500
T3
C
u
2000
1500
1000
s V. ^
«h m in
\ ^ \ x
U3 ID U} U3 U)
- Conductivity
fN fM fN
lOlOlOvOlDlOlOlDlDlO
Set Point
-High
Figure s. Conductivity trend using manual or timed control.
Source; Federal Energy Management Program.
4000
3500
>¦
3000
>
3
2500
"O
c
u
2000
1500
1000
-BD Control
-High
Figure 9. Conductivity trend using a conductivity controller
to initiate blowdown. Source: Federal Energy Management
Program.
establish a target CoC. There will be a relationship
between these parameters and conductivity, based
on the water chemistry specific to a site.
Understanding the target CoC and installing a
controller that initiates blowdown based on the
associated conductivity are proven techniques
to help improve tower water efficiency. The
conductivity controller opens a blowdown valve
as needed to maintain the controlling parameter
within acceptable limits (rather than manually or
on a set timer). Figure 8 and Figure 9 above show
the impact a conductivity controller can have
compared to manual or timer-based blowdown.
CM
WaterSense
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Water Efficiency in Laboratories
In addition to a conductivity controller, flow
meters should be installed on make-up and
blowdown lines and connected to a building
automation system, wherever possible. Meters
that display total water use and current flow rate
provide useful information about the status of the
tower and cooling system, and they should be
checked regularly to quickly identify problems.
For example, as shown in the Understanding
Cycles of Concentration box on page 24, the
conductivity of make-up water and blowdown can
be compared with the ratio of blowdown volume
to make-up volume. If both ratios are not about
the same, the tower should be checked for leaks or
other unwanted draw-offs. It is worth noting that
submetering of the cooling tower make-up and
blowdown can be used to document evaporative
water consumption (i.e., water that is not being
discharged to the sewer). In some municipalities,
this information can be used to obtain a reduction
in sewer charges.
It is important to select a water treatment vendor
carefully—one who understands that water
efficiency is a high priority. Vendors should
provide estimates of the quantities and costs of
the treatment program (e.g., chemical costs),
blowdown water volumes, and expected CoC.
Criteria for selecting a vendor should include the
estimated cost of treating 1,000 gallons of make-up
water and the highest recommended CoC for
the water system. Treatment vendors may also
be able to offer recommendations for filtration,
water softening, or other special water treatment,
discussed in more detail below, to help improve
water efficiency and reduce overall operating
costs.
Efficient Cooling Tower Design and Selection
New construction and renovation projects are
excellent opportunities to design for greater water
and energy efficiency. Labs can employ a number
of options to reduce cooling demand or operating
frequency of the cooling tower, including
non-evaporative cooling equipment, hybrid
cooling towers, heat recovery, and economizers.
Non-Evaporative Cooling Equipment
Consider air-cooled chillers, air-source heat
pumps, ground-source heat pumps, or dry coolers
to produce cooling to meet lab building cooling
loads. These systems utilize non-evaporative
forms of heat rejection and eliminate the need
for cooling towers and their associated water
consumption. Given the large cooling load
capacity for lab buildings, hybrid systems that
utilize non-evaporative cooling strategies as the
first form of cooling and utilize cooling towers
only for peak cooling capacity can recognize
significant savings in cooling tower make-up
water. The energy consumption for these systems
must be balanced with water savings, though. For
example, air-cooled chiller plants typically have
lower efficiencies than water-cooled chiller plants
serving large lab buildings. On the other hand,
recent trends in the building design industry to
reduce fossil fuels for heating have led to more
labs utilizing air-source heat pumps for both
heating and cooling, with the added benefit of
reducing or eliminating water consumption for
cooling towers.
Hybrid Cooling Towers
Hybrid towers have both a wet and a dry cooling
section. The wet cooling section provides
evaporative cooling on hotter days, whereas the
dry cooling section is used when the outside air
temperature is low enough to provide sufficient
cooling, operating similar to an air-cooled chiller.
Hybrid towers can significantly reduce water
consumption compared to typical cooling towers,
since water is not consumed when the hybrid
tower is operating in dry mode. Hybrid cooling
tower performance depends on the location and
environmental characteristics of the site. Energy
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Water Efficiency in Laboratories
and water costs also play a crucial role in the
decision to use hybrid cooling towers, because
making some of these towers more water-efficient
could have a negative impact on energy efficiency
Hybrid cooling towers can also help with plume
abatement. A cooling tower's plume is the visible
column of saturated air exiting a conventional
cooling tower. A smaller plume is desirable
in many residential areas and in areas where
visibility is important, such as near airport
runways.
Heat Recovery
The purpose of a cooling tower is to get rid of
unwanted heat within the recirculating water loop.
However, laboratory facilities commonly include
24/7/365 cooling loads that are simultaneous with
reheat or building heating loads, providing a use
for the waste heat. A heat recovery heat pump/
chiller can be installed to pre-cool chilled water
upstream of the building chillers, and reject the
waste heat from that first stage of cooling to serve
heating loads on the building hot water loop. This
directly reduces the cooling load experienced
by the water-cooled chillers and cooling towers,
thus reducing evaporation, as well as the amount
of energy and fossil fuels needed to provide
heating to other applications. Newer lab designs
attempt to maximize water-cooled process cooling
equipment on the chilled water loop to increase
these simultaneous heating and cooling loads for
energy recovery.
Somewhat related, airside energy recovery
systems can reduce the amount of energy needed
to heat and humidify or cool and dehumidify
ventilation air for a lab, and thus the water
consumption for humidification and/or cooling.
Non-hazardous lab exhaust can generally be
routed through a total energy recovery wheel
to transfer both thermal energy and moisture
from the exhaust air to the incoming outside air.
This type of energy recovery is not permissible
from hazardous exhaust airstreams, but the
thermal energy from hazardous exhaust can
be extracted by heat recovery coils, which can
reduce the cooling load to condition outside air
in the warmer months. For new construction and
major renovations, some form of heat recovery
may be required under the International Energy
Conservation Code (IEGG), which has been
adopted by many jurisdictions, depending on the
climate zone for your location.
Economizers
Both air- and water-side economizers can be used
to reduce both energy and water use. Air- and
water-side economizers work by utilizing cold,
outside air (when it is available) to provide space
or chilled water cooling rather than depending
on mechanical cooling. This is often referred to as
"free cooling." When mechanical cooling would
have otherwise been provided by a chiller and
cooling tower, reducing the amount of mechanical
cooling has commensurate water savings.
ENERGY STAR® provides information on how to
use these technologies effectively (ENERGY STAR,
2022a; ENERGY STAR, 2022b).
If pursuing air-side economizers, laboratories
should consider humidification requirements,
as cold air can often be dry. The energy and
water demand from humidification can impact
the cost-benefit of using this technology. Note
that cooling tower make-up water demands are
typically low in the winter, so this strategy may
not save as much water as other energy recovery
strategies.
Alternative Water for Cooling Tower Make-Up
Another opportunity to reduce water costs
associated with cooling tower operation is to
identify and utilize appropriate onsite alternative
water sources as make-up. Rainwater or
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Water Efficiency in Laboratories
condensate from HVAC cooling coils are both
good options for supplying water with low
dissolved solids to the cooling tower. See the
Alternative Water Sources section on page 32 for
more information.
Whether pursuing condensate recovery, rainwater
collection, or another alternative water source,
work with the laboratory's treatment vendor to
understand whether additional water treatment or
other maintenance will be necessary.
Special Water Efficiency Features
Water-efficient special features that can be
incorporated into cooling tower systems include
side-stream filtration, water softening, and
alternative water treatment systems.
Side-stream filtration systems remove suspended
sediment and minerals from a portion of the
recirculating water. These systems increase
energy and water efficiency and require less
chemical treatment because they draw water
from the sump, filter out sediment (which reduces
microbiological growth that could otherwise lead
to issues like corrosion, scaling, and fouling), and
return filtered water to the tower. Side-stream
filtration is particularly helpful for systems that are
subject to dusty atmospheric conditions. Be sure
to consider water used to periodically backflush
(i.e., clean) the filters when evaluating overall
project savings (DOE/EERE/FEMP, 2012a).
If high water hardness limits the GoG that can be
achieved, consider using a water softener to treat
all or some of the cooling tower make-up water.
Water softeners remove scale-forming minerals
(e.g., calcium, magnesium) from the incoming
water supply, which would allow increased
GoG within the tower. It is worth noting that
softened water can be more corrosive, so work
with the treatment vendor to ensure appropriate
corrosion inhibitors are applied to the tower. Also
consider ongoing operations and maintenance
and salt costs associated with the softener prior to
pursuing this project type.
More recently, a number of alternative or
innovative cooling tower treatment technologies
have become available that can increase
cycles of concentration, improve energy and
water efficiency, reduce chemical use, and
potentially provide ancillary benefits including
legionella control and reduced maintenance.
These technologies use a variety of treatment
mechanisms. The U.S. General Services
Administration (GSA) reviewed the efficacy
of some of these technologies and confirmed
effectiveness and savings claimed (GSA, 2022).
Laboratories should consider whether these
technologies could be beneficial in reducing water
used for cooling.
Steam Boiler Water Efficiency
Both steam and hot water boilers may be
present within a laboratory. The operation and
maintenance requirements for steam boilers are
similar in nature to that of cooling towers and
chilled water systems, in as much as periodic
blowdown and water treatment are required to
maintain water quality and energy efficiency.
Steam boilers use (and lose) water primarily
from condensate loss and blowdown, as well as
the tempering water required for both of these
discharges. Given recent trends in the building
design industry to move away from utilizing fossil
fuels in new designs, steam boilers are often
being replaced with lower temperature hot water
systems for building heating and local electric
steam generators for humidification, sterilization,
or other process loads.
In general, hot water boilers are not a target
for water efficiency. On open systems used to
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Water Efficiency in Laboratories
supply hot water for end uses [e.g., handwashing,
cooking, cleaning), water and energy savings
should be targeted by reducing hot water use
rather than boiler improvements. On closed-loop
hot water systems typically used for space heating
water consumption should be minimal. However,
consider installing a make-up meter on the closed
loop system to help identify leaks.
Steam Condensate Collection
Steam boilers generate steam that is distributed
through a laboratory, either for space heating or
process use (e.g., within sterilizers). As the steam
cools, it recondenses into hot water, which is
either discharged to the sewer or captured and
returned to the boiler for reuse. Prior to any sewer
discharge, condensed steam must be cooled to
140°F or less, often through use of tempering
water, which also contributes to the overall water
use requirements of boiler operations.
Recovery and return of condensate to the boiler
system has substantial potential for reducing both
water and energy use. Recovering condensate not
only reduces make-up water demand, but it also
reduces tempering water requirements, reduces
the frequency of blowdown (note that condensate
is very low in dissolved solids), and, because it is
still hot, requires much less energy to reproduce
steam than the cool incoming water supply.
Within a condensate recovery system, leaking
steam traps and failed condensate pumps can be
a source of water and energy waste. Leaking traps
allow steam to pass through to the condensate
recovery system. This steam/condensate mix will
travel through condensate piping to a condensate
receiver. The receiver is intended to collect the
liquid condensate and pump it back to the boiler.
Pressurized steam in the receiver can damage
Figure 10. Example of steam plume from a roof vent,
indicating a failed steam trap.
the pumps; therefore, the receivers are vented to
the atmosphere, which wastes energy and water.
It is good practice to periodically walk around
the outside of the building and look for steam
plumes or wisps coming from roof vents (shown
in Figure 10 above), especially in winter, which can
be an indication of a failed steam trap. Similarly,
poorly maintained condensate pumps that are not
functioning properly can result in hot condensate
overflowing the receiver and discharging to the
drain. A good maintenance program should
regularly check and repair steam traps and
pumps, which can save a significant amount of
energy and water. Steam trap repairs and failed
condensate pump replacements usually pay for
themselves within weeks or months.
If condensate recovery is not feasible, laboratories
can explore methods for reducing the temperature
of condensate prior to discharge without the use
of tempering water. In place of tempering water, a
flash tank, expansion tank, and/or aftercooler may
be able to be used to reduce the temperature of
condensate prior to discharge. If tempering water
is needed, evaluate whether this can be provided
from a non-potable water source and make sure
that any valves that supply tempering water cut off
cleanly when tempering water is not needed.
cfsn a
28 \ \ 1 / / i
WaterSense
-------
Water Efficiency in Laboratories
Using Heat Recovery in a Boiler Plant to Save Energy and
Eliminate Water Used for Tempering
Heat recovery can be used to eliminate the need for tempering water on boiler blowdown or condensate
drains. In the schematic below, steam boiler blowdown is initially vented to a small flash tank and flashed
down to about 5 pounds per square inch (psi.i gauge. The flash steam from a boiler plant operating at
100 psi will be about 10% of the mass flow. Water and embedded energy in the flash steam can be fully
recovered by routing this flash steam back to the deaerator. The remaining liquid, now at approximately
230°F, is directed through a tube-bundle stainless steel heat exchanger inserted into a 350- to 500-gallon
pressure vessel. The heat is transferred to the incoming make-up water. The flow of condensate and
blowdown are often not simultaneous, so the large tank acts as a thermal flywheel and stores thermal
energy. After entering the heat exchanger, the blowdown is cooled to around 85° to 90°F, completely
eliminating the need for tempering water before being discharged to the drain.
Figure 11. Example design for boiler blowdown heat recovery.
Source: Dan Doyle, Grumman/Butkus Associates
(*I2SE A
29 V\ I III
WaterSense
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Water Efficiency in Laboratories
Steam Boiler Blowdown Control and Water
Management
As a boiler generates steam, dissolved solids
and minerals are left behind in the boiler
system (similar to what happens when water
is evaporated from a cooling tower). High
concentrations of dissolved solids can cause
scale and corrosion of the equipment, leading
to inefficiencies or other maintenance concerns.
Therefore, a portion of the water in the steam
boiler system must be periodically blown down.
Make-up water is subsequently added to maintain
the system's water volume.
First and foremost, metering and monitoring
boiler water use and performance should be
an integral part of regular operations and
maintenance. If possible, meters should be
connected to the facility's building automation
system or central control dashboard. Beyond
metering, work with a water treatment vendor
to address water chemistry and help manage the
boiler system for efficiency. Blowdown should
be activated using a conductivity-based control
system rather than continuously or on a set timer.
Conductivity controllers only initiate blowdown
when dissolved solid concentration reaches a
preset threshold. Unnecessary blowdown wastes
water, energy, and chemicals.
If tempering water is used to cool blowdown,
reducing blowdown can also reduce tempering
water use. Similar to with condensate cooling,
there may be viable options to reduce the
temperature of blowdown prior to discharge
without use of tempering water. A flash tank or
heat exchanger can be used. Heat exchangers can
be used to preheat boiler make-up water, which
reduces boiler energy demand (DOE/EEBE, 2012).
Another option to reduce blowdown frequency
is to improve incoming water quality through
pre treatment of make-up water using a water
softener or reverse osmosis system. Make sure
to consider the additional water or operational
costs that may occur during use of pretreatment
and pursue efficient operation of these systems.
See the Water Treatment and Purification System
section on page 7 for more information.
Other Typical Building Water Loads
While cooling towers, boilers, and specialty
laboratory equipment can consume significant
amounts of water, laboratories often have water
loads typical of other commercial buildings, such
as those associated with restrooms (sanitary),
outdoor (irrigation), and, in some cases, onsite
commercial kitchens or laundries. Water use in
these areas should not be overlooked when
devising a water efficiency strategy. Often
measures in these areas can be simple and cost-
effective. This section provides a brief overview of
sanitary fixture, outdoor, and commercial kitchen
and laundry water use and savings opportunities.
For more detailed guidance on improving
efficiency in these areas, review WaterSense at
Work.
Sanitary Fixtures
There are a variety of ways to save water in
restrooms; for example, maintenance staff should
inspect sanitary fixtures for leaks regularly. They
should also check and adjust automatic sensors
on toilets, urinals, and faucets, if installed, to
ensure they are operating properly to avoid
double or phantom flushing or running when
unnecessary. Old toilets, urinals, showerheads,
and certain lavatory faucets can be replaced with
WaterSense labeled models. The faucets used in
most commercial lavatories and lab handwashing
stations are not able to earn the WaterSense label,
but 0.5 gallon-per-minute faucets and aerators are
available for this purpose.
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Water Efficiency in Laboratories
EPA Product Labeling Programs Ensure Water
Efficiency
The U.S. Environmental Protection Agency's WaterSense
program labels plumbing and irrigation products that are
independently certified to use at least 20% less water and
perform as well as or better than standard products on the
market. As applicable, ENERGY STAR certified products are
also required to address water efficiency. See the box below to
determine which water-using fixtures within a lab can earn the
WaterSense or ENERGY STAR labels.
look for
ENERGYSTAR
Look for the WaterSense or ENERGY STAR Label on Water-Efficient
Indoor and Outdoor Products
Product Category
WaterSense
Plumbinq Products
ENERGY STAR
Toilets
Flushing Urinals
Private-Use Lavatory
Faucets
Public-Use Lavatory
Faucets
Showerheads
Kitchen Faucets
Irrigation Controllers
~
~
V
Irrigation Products
Spray Sprinkler
Bodies
V
Commercial Kitchen and Laundry
Clothes Washers
Dishwashers
Commercial Ice
Makers
Commercial
Combination Ovens
Commercial Pre-Rinse
Spray Valves
Now DOE-Compliant
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Water Efficiency in Laboratories
Professionals certified by a WaterSense labeled
program understand water efficiency concepts
and are qualified to design, install, and/or audit
irrigation systems. For labs with their own
landscape maintenance staff, WaterSense has a
design guide for micro irrigation and other helpful
resources on outdoor water savings. Visit www,
epa.crov/watersense/outdoors to learn more.
Commercial Kitchen and Laundry Equipment
Some laboratories may have onsite commercial
kitchens or laundries. Water (and energy from
generating hot water or steam) used by these
types of ancillary operations can be significant.
From food preparation to dish cleaning, common
sources of water-using equipment in labs'
commercial kitchens include commercial ice
machines, combination ovens, steam cookers,
steam kettles, dipper wells, pre-rinse spray valves,
food disposals, commercial dishwashers, and
wash-down sprayers.
Because many of these appliances use heated
water, ensuring commercial kitchen equipment
uses water efficiently saves the facility energy
as well. When specifying or replacing these
appliances, look for ENERGY STAR certified ice
machines, dishwashers, combination ovens, and
steam cookers. For appliances not certified by
ENERGY STAR, check typical energy and water
use when selecting new equipment.
Some laboratories may also have onsite laundry
facilities with equipment such as single- or
multi-load washers, washer extractors, and tunnel
washers. Recent advances in commercial laundry
equipment, including the availability of more
efficient equipment, water recycling, and ozone
technologies, have provided options for reducing
water use in nearly all commercial laundry
operations. ENERGY STAR certified clothes
washers address both energy and water efficiency.
Other ways to save water in kitchens and laundry
facilities in labs include: replace older kitchen
appliances, dishwashing equipment, and laundry
equipment with ENERGY STAR certified models;
replace old pre-rinse spray valves with flow
rates of 1.6 gpm or higher with high efficiency,
DOE-compliant models; wash only full loads of
dishes and laundry; and consider adding ozone
or water recycling capabilities to existing laundry
equipment.
Alternative Water Sources
Laboratory buildings are good candidates for
alternative water sources, because many of their
end uses could be supplied by non-potable water.
Check out WaterSense at Work for detailed water-efficient practices related to sanitary fixtures, irrigation
and landscaping, and commercial kitchen and laundry eguipment:
www.epa.CTOv/watersense/best-manaCTement-practices.
Learn about WaterSense and ENERGY STAR product and appliance specifications:
www.epa.gov/watersense/watersense-products:www.energvstar.gov/products
Explore WaterSense's outdoor resources, including certified irrigation professionals:
www, ep a. gov/water sense/ outdoors
Review ENERGY STAR commercial kitchen resources:
www.energvstar.gov/partner resources/energy star training center/commercial food service
Resources on Water-Saving Equipment
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Water Efficiency in Laboratories
Water used for equipment cooling,
cooling tower make-up, irrigation,
exhaust air scrubbers, and toilet and
urinal flushing does not need to be
potable; therefore, there may be
opportunities to use alternative sources
of water.
Alternative sources of water include those
generated onsite (e.g., condensate, rainwater) or
supplied by a wastewater utility (e.g., reclaimed
water). Following are some ways that laboratories
can collect and use alternative sources of water to
reduce potable water use, conserve potable water
for drinking water, and reduce water and sewer
costs.
The two most useful alternative water sources
for laboratory buildings are HVAC cooling coil
condensate recovery and rainwater harvesting.
In certain climates, both can provide fairly
steady sources of relatively pure water. Use of
these sources is limited primarily by the cost
of capturing and storing the water. EPA has
developed the Non-potable Environmental
and Economic Reuse (NEWR) Calculator as
a screening-level assessment of onsite reuse
potential. While not specifically targeted to
laboratories, the tool can estimate condensate and
rainwater collection and reuse potential based on
building-specific characteristics.
RO system reject water may also provide relatively
consistent quality and quantity of water that can
be reused. Lastly, wastewater treatment plants
may supply reclaimed effluent, which is often
cheaper than potable water and can be used for
nonpotable uses.
HVAC Condensate Recovery
In many places in the United States, mechanical
space cooling generates significant quantities of
HVAC condensate, as warm humid air is cooled
and dried for temperature and humidity control.
The condensate from HVAC cooling coils in air
handling units, fan coils, dehumidifiers, and
refrigeration units can provide facilities with a
steady supply of relatively pure water for many
processes.
Laboratories are excellent sites for
condensate recovery, because they
typically require dehumidification of
a large amount of outside air, and the
greatest volumes of reclaimed HVAC
condensate are available at the times
of greatest nonpotable water demand
for cooling tower water make-up.
The potential for condensate recovery depends
on many factors, such as ambient temperature,
humidity, load factor, equipment, and size.
FEMP has developed a map to communicate
condensate collection potential across the United
States. However, cost-effective implementation
of condensate recovery and use can be feasible
anywhere given the right circumstances.
Condensate water is relatively free of minerals
and other solids. In most cases, it is similar in
quality to distilled water. This makes it an excellent
source for cooling tower make-up, since there is
a good seasonal correlation between condensate
supply and cooling tower demand. Due to its
lower temperatures and higher quality, utilizing
condensate as cooling tower make-up water
allows cooling towers to achieve higher cycles
of concentration and can reduce chemical usage.
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Water Efficiency in Laboratories
EPA's Collection of Air-Handler Condensate Projects Throughout the United States
EPA owns and operates many research and analysis laboratories throughout the United States that
conduct scientific research and analysis supporting national and regional environmental programs. As
part of comprehensive water assessments at each facility staff evaluated potential sites where air-handler
condensate recovery was practically feasible and cost-effective. Good candidates were facilities:
• In hot and humid climates with greater condensate generation and higher cooling loads;
• With larger capacity air handlers (rather than smaller units spread throughout the facility), which
minimizes the number of collection points;
• Those that had collection points close to the cooling tower basin or recirculating water lines, which
reduces the amount of piping; and
• Where major wall or roof intrusions were not required, and other physical obstacles were not an
issue.
EPA subsequently implemented air-handler condensate collection and reuse projects at many of these
labs. Some examples, including the location, annual gallons collected, and proportion of cooling tower
make-up demand, are shown in the table below.
Location
Total Cooling Tower
Capacity
Annual Gallons Collected
Aproximate Percent of
Cooling Tower Make-Up
Ada, OK
450 tons
200,000
23%
Athens, GA
300 tons
460,000
37%
780 tons
340,000
23%
Chelmsford, MA
Unknown
140,000
17%
Edison, NJ
400 tons
100,000
10%
Fort Meade, MD
2,400 tons
180,000
8%
Gulf Breeze, FL
450 tons
450,000
18%
Kansas City, KS
1,400 tons
310,000
18%
Condensate can also reduce the temperature of
condenser water, allowing chillers to operate more
efficiently and save energy as well. Condensate
can typically be fed directly into the cooling tower
basin as make-up water without any treatment.
Condensate can also be used as boiler make-up,
RO feed water, or drip irrigation without special
treatment.
Condensate should not be considered potable,
as it can contain dissolved contaminants and
bacteria, such as legionella, because it is not
chemically treated. It is best to use condensate
in a process that provides an additional level of
biological treatment, namely cooling towers, but
could also include boilers or ornamental fountains.
Collected condensate can also be used for drip
irrigation. If using condensate for spray irrigation
or toilet and urinal flushing, however, condensate
should be filtered and disinfected. Normal chlorine
feed equipment, ozone, or ultraviolet disinfection
can be effective (San Antonio Water System, 2013).
Rainwater Harvesting
Rainwater from building roofs is another excellent
source of nonpotable water. It can be used in many
of the applications in which condensate recovery
water is used. Typically, however, rainwater
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Water Efficiency in Laboratories
contains fewer impurities than potable water from
a public drinking water supply. The only cost is the
capital cost of equipment to collect and store the
water (which can be significant).
Since rainwater and melted snow are collected
throughout the year, the demands for rainwater
should be year-round as well. Cooling tower
and irrigation water demand is usually low in
the winter; therefore, collected rainwater can
be directed to water closets and urinals during
these times. However, utilizing reclaimed water
for this purpose typically requires higher levels of
filtration and chemical treatment than for uses like
cooling towers and irrigation.
Rainwater systems typically consist of six
elements: the roof catchment area; gutters,
downspouts, or roof drains; leaf screens, vortex
filters, and roof washers that remove larger debris
and contaminants; cisterns or storage tanks; a
pumping and conveyance system; and a treatment
system.
Stormwater from impervious surfaces other
than rooftops can also be collected. However,
because stormwater is not as high-quality as
rooftop rainwater, it is best to reuse stormwater
reclaimed from surfaces other than rooftops
only for irrigation. Run-off from parking lots in
northern climates may contain road salt and oil
from vehicles; therefore it may not be suitable for
irrigation.
The storage tank or cistern requires the most
coordination and space of these components. It
can be either above or below ground, but should
be close to supply and demand points to minimize
piping needs. It should have a tight-fitting lid to
prevent evaporation and to keep out mosquitoes,
animals, and sunlight (which allows algae to
grow).
Laboratories considering the use of rainwater
should check with local or state governments
about possible restrictions. There are some states
that restrict rainwater use. The restrictions have
to do with water rights laws, which are complex
and vary according to the jurisdiction. Some
allow facilities to detain water for irrigation and
other uses that return the water back to the
system, but they do not allow water to be retained
permanently onsite. In addition to a Rainwater
Harvesting Tool. FEMP has developed a map that
summarizes state-bv-state rainwater harvesting
regulations. The American Rainwater Catchment
Systems Association (ARCSA) has helpful
documents on the use of rainwater.
Rainwater and condensate recovery systems
can be expensive to install as retrofits. Storage
capacity and treatment systems in particular
can be expensive. However, properly sizing the
system to match demand to supply could greatly
reduce costs. For example, many condensate
recovery systems that are used for cooling tower
make-up do not require significant storage, since
condensate supply will always be less than cooling
tower demand. However, beyond water cost
savings, laboratories should consider potential
system improvements and other ancillary benefits
(e.g., reduced chemical use) from the use of
high-quality alternative water sources.
RO Reject Water
Reverse osmosis systems, which use a membrane
to remove impurities and create higher purity
water, generate a stream of reject water that
contains the impurities that were removed during
the process. RO systems can achieve a recovery
rate of 50% to 75% (with larger, centralized
systems commonly used by laboratories likely able
to achieve the high end of this recovery range).
However, this means that 25% to 50% of water
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Water Efficiency in Laboratories
and fire protection systems (USGS, 2018). While
not treated to drinking water quality, reclaimed
wastewater can serve as a cost-effective,
high-quality, and reliable source of water that can
be used to reduce potable water use and costs
within a laboratory.
entering the system is part of the reject, which is
commonly sent down the drain. Since many
laboratories use large volumes of RO water for
research and specialized processes, the available
quantity of RO reject water has the potential to be
significant. Similar to rainwater, RO reject water
is available year-round, and is best utilized for
year-round demands such as toilet flushing.
While reject water is lower quality than water
supplied by a laboratory's water utility, in most
cases there may be opportunities to reuse this
waste stream for other purposes. End uses can
include toilet and urinal flushing, cooling tower
make-up, irrigation, or ornamental fountain
make-up. If using RO reject as cooling tower
make-up, make sure that the concentration of TDS
and other constituents of the RO reject water are
less than the those of the recirculating water flow.
Similar to condensate and rainwater collection,
implementing RO reject water recycling can be
more expensive as a retrofit, depending on the
storage, treatment (if applicable), and piping
needed. If graywater systems exist within a
laboratory, RO reject can be diverted to these
systems. New lab designs often combine the
HVAC condensate, rainwater, and RO reject into
the same cistern and treatment system to reduce
overall space, complexity, cost, and maintenance
of the reclaimed water system.
Reclaimed Wastewater
Reclaimed wastewater (sometimes referred to
as recycled or "purple pipe" water) is an option
when a laboratory has access to municipal
wastewater that has been treated to a secondary
disinfection level, or when treated wastewater can
be generated cost effectively onsite. Reclaimed
wastewater can be used for some nonpotable
applications, such as cooling tower make-up,
boiler make-up, irrigation, vehicle washing,
Laboratories should check with their local water
and/or wastewater utility to determine the local
availability and associated cost of reclaimed
wastewater. In addition, before using reclaimed
wastewater sourced within the building, it is
important to understand local requirements for
water quality for the intended uses for that water.
Use of reclaimed water often requires the posting
of clear signage to indicate reclaimed water
is used and is not fit for human consumption.
Further, reclaimed water quality can vary by
location, and while it is generally fit for nonpotable
uses, reclaimed water can be harsher on some
fixtures or equipment. The utility providing
the reclaimed water, or a laboratory's onsite
wastewater treatment plant, should be
able to provide insight on different water quality
parameters such as conductivity, TDS, alkalinity,
biological oxygen demand, and pH. Many
plumbing and irrigation manufacturers sell
products that are intended for reclaimed water
applications. Beyond purple or blue dyes for the
water and purple coloration for pipes, signage,
and fixtures to indicate reclaimed water use, these
products often have added features and are made
of materials that can withstand harsher conditions
typical of reclaimed water.
When considering the use of reclaimed
wastewater within cooling towers, it is important
to understand the reclaimed water quality and
work closely with a qualified treatment vendor
who has experience with reclaimed water.
Depending on the type of materials used in the
cooling tower, piping, and heat transfer units,
there may be special considerations that could
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Water Efficiency in Laboratories
impact the ability to use reclaimed water. A
qualified treatment vendor should be able to
communicate changes to the treatment program
and associated cost impacts. In some cases, due to
high chlorine and phosphate in reclaimed water,
the cost of cooling tower water treatment may
actually go down. However, some additional water
monitoring, chemical feed systems, or biological
control may be necessary (Puckorius, 2013).
Acknowledgements
An earlier version of this guide was published as part of the Laboratories for the 21st Century (Labs21)
tool kit. The principal author of the original version was Stephanie Tanner, then of the National
Renewable Energy Laboratory (NREL), now the lead engineer for EPA's WaterSense program.
Contributors and reviewers included Bill Hoffman, PE, of H.W. Hoffman and Associates; James Kohl of
URS Corp; Roy Sieber of Eastern Research Group, Inc. (ERG); and Otto Van Geet, PE, Nancy Carlisle,
ALA. and Sheila Hayter, PE, of NREL.
Revision Authors
Stephanie Tanner, EPA WaterSense
Robert Pickering and Kim Wagoner, PE, ERG
Bill Hoffman, PE, H.W. Hoffman and Associates, LLC
Other Contributors
Jacob Werner, Perkins & Will and Patrick Murphy, PE, Vanderweil Engineers
Revision Reviewers
Daniel Doyle, PE, Grumman/Butkus Associates
Greg Eades, Ph.D., P.E., EPA Office of Research and Development
Patrick Murphy, PE, Vanderweil Engineers
Otto Van Geet, PE, NREL
References
Aldred Cheek, Kristin and Nancy M. Wells. 2020. Changing Behavior Through Design: A Lab Fume
Hood Closure Experiment. Frontiers in Built Environment. January 2020. Volume 5. Article 146.
American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). 2020. 2020
ASHRAE Handbook-HVAC Systems and Equipment. Chapter 22: Humidifiers.
ASHRAE and ICC. 2020. ANSI/ASHRAE/ICC/USGBC/IES Standard 189.1-2020. Standard for the Design
of High-Performance Green Buildings Except Low-Rise Residential Buildings.
-------
Water Efficiency in Laboratories
Beecher, Janice A. 2020. Trends in consumer expenditures and prices for public utilities (2020). Institute
of Public Utilities, Michigan State University, https://ipu.msu.edu/wp-content/uploads/2020/02/
IPU-MSU-CPI-CES-2020-l.pdf
Black and Veatch Management Consulting. 2021. 2021 50 Largest Cities Water and Wastewater Report.
April 2021.
Bosley, Mark. 2012. Beverse Osmosis for Laboratory Use. International Pharmaceutical Industry. Summer
2012. Volume 4. Issue 3.
Consolidated Sterilizer Systems. 2021. Eco-Friendly Autoclave Solutions. February 2021. https://
consteril.com/wp-content/uploads/2021/02/CSS-Sustainabilitv-Brochure-2Q21.pdf
Department of Energy (DOE), Office of Energy Efficiency and Benewable Energy (EEBE), Advanced
Manufacturing Office. 2012. Becover Heat from Boiler Blowdown. January 2012. www.enercrv.crov/sites/
prod/files/2014/05/fl6/steaml0 boiler blowdown.pdf
DOE, EEBE, Federal Energy Management Program (FEMP). 2012a. Side Stream Filtration for Cooling
Towers. October 2012. www.enercrv.crov/sites/default/files/2013/10/f3/ssf coolincr towers.pdf
DOE, EEBE, FEMP. 2012b. Fume Hood Sash Stickers Increases Laboratory Safety and Efficiency at
Minimal Cost: Success at Two University of California Campuses. March 2012. https://wwwl.eere.
enercrv.crov/femp/pdfs/sash stickers cs.pdf
DOE, EEBE, FEMP. 2013. Beverse Osmosis Optimization. August 2013. www.enercrv.crov/sites/default/
files/2013/10/f3/ro optimization.pdf
East Bay Municipal Utility District (EBMUD). 2008. WaterSmart Guidebook—A Water-Use Efficiency
Plan Review Guide for New Businesses, www.ebmud.com/water/conservation-and-rebates/commercial/
watersmart-cruidebook/.
ENEBGY STAB. 2022a. Use an Air-Side Economizer, www.enercrvstar.crov/products/use air side
economizer. Accessed January 24, 2022.
ENEBGY STAB. 2022b. Consider Water Side Economizers, www.enercrvstar.crov/products/consider
water side economizers. Accessed January 24, 2022.
Environmental Protection Agency (EPA). WaterSense at Work: Best Management Practices for
Commercial and Institutional Facilities, www.epa.crov/watersense/best-manacrement-practices.
Grist, Matthew, Dave Perkin, and David M. Barber. 2013. Introducing a Novel and Highly Efficient
Water-Saving Condenser. ACS Sustainable Chem. Eng. 2013,1,12,1498-1501. September 17, 2013.
Koeller, John, et al. 2004. A Report on Potential Best Management Practices. Prepared for the California
Urban Water Conservation Council. August 2004. https://calwep.orcr/wp-content/uploads/2021/03/
Steam-St.erilizer-Betrofit-PBMP-2004.pdf
-------
Water Efficiency in Laboratories
National Institutes of Health (NIH). 2013. Laboratory Water. NIH Office of Research Facilities (ORF)
Division of Technical Resources (DTR). March 2013. https://orf.od.nih.crov/TechnicalResources/
Documents/DTR%20White%20Papers/Laboratorv%20Water-Its%20Importance%20and%20
Application-March-2013 508.pdf
Puckorius, Paul R. 2013. "Recycled Water for Cooling Towers: Good Idea or Bad?" Water Technology.
February 1, 2013. www.watertechonline.com/process-water/article/16212383/recvcled-water-for-
coolincr-towers-crood-idea-or-bad
Radleys. UCSD Chemistry standardises on Findenser for safety and sustainability. www.radlevs.com/
case-studies/ucsd-chemistrv-standardises-on-findenser-for-safetv-and-sustainabilitv/. Accessed January
24, 2022.
San Antonio Water System. 2013. San Antonio Condensate Collection and Use Manual for Commercial
Buildings. https://apps.saws.orcr/Conservation/Commercial/Condensate/docs/SACCUManual 20131021.
pdf
Stanford University Environmental Quality and Water Efficiency Group. 2013. Fact Sheet on Steam
Sterilizers at Stanford University. December 2013. https://suwater.stanford.edu/sites/cr/files/sbivbil9876/
files/media/file/sem steamsterilizers Stanford 2013.pdf
University of Colorado Boulder. Waterless Condensers. CU Green Labs Program, www.Colorado,
edu/ecenter/crreenincr-cu/cu-crreen-labs-procrram/lab-water-efforts/waterless-condensers. Accessed
December 8, 2021.
U.S. General Services Administration (GSA). 2022. AWT: GSA Guidance for Cooling Towers, www.crsa.
crov/crovernmentwide-initiatives/climate-action-and-sustainabilitv/emercrincr-buildincr-technologies/
published-findincrs/water/awt-crsa-cruidance-for-coolincr-towers. Accessed January 24, 2022.
U.S. Geological Survey (USGS). 2018. Reclaimed Wastewater. June 8, 2018. www.uscrs.crov/special-topic/
water-science-school/science/reclaimed-wastewater. Accessed December 8, 2021
Watch, Daniel and Deepa Tolat. 2016. Sustainable Laboratory Design. August 19, 2016. www.wbdcr.orcr/
resources/sustainable-laboratorv-desicrn. Accessed January 24, 2022.
Zynda, Jeffrey R. 2015. "A shift in designing cage-washing operations." Lab Animal. Volume 44, No. 4.
April 2015.
Additional Resources
American Rainwater Catchment Systems Association (ARCSA). www.arcsa.orcr/
ENERGY STAR. www.enercrvstar.crov/
EPA. Non-Potable Environmental and Economic Water Reuse (NEWR) Calculator, www.epa.crov/
water-research/non-potable-environmental-and-economic-water-reuse-newr-calculator
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Water Efficiency in Laboratories
EPA WaterSense Program, www.epa.crov/watersense
EPA WaterSense Program. 2021. Water-Smart Landscaping, www.epa.crov/watersense/landscapincr-tips
EPA WaterSense Program. WaterSense at Work: Best Management Practices for Commercial and
Institutional Facilities, www.epa.crov/watersense/best-manacrement-practices
FEMP. Alternative Water Sources Maps. www.enercrv.crov/eere/femp/alternative-water-sources-maps
FEMP. Water Evaluation Tools, www.enercrv.crov/eere/femp/articles/water-evaluation-tools
International Institute for Sustainable Laboratories (I2SL). Laboratory Benchmarking Tool. https://lbt.
i2sl.org/
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