WaterSense
at Work

Laboratory and Medical Equipment

7.4 Glassware Washers



Best Management Practices for
Commercial and Institutional Facilities

*

EPA

WaterSense

March 2024


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WaterSenseฎ is a voluntary partnership program sponsored by the U.S. Environmental
Protection Agency (EPA) that seeks to protect the nation's water supply by transforming
the market for water-efficient products, services, and practices.

WaterSense at Work \s a compilation of water efficiency best management practices
intended to help commercial and institutional facility owners and managers from multiple
sectors understand and better manage their water use. It provides guidance to help
establish an effective facility water management program and identify projects and
practices that can reduce facility water use.

An overview of the sections in WaterSense at Work is below. This document, covering
water efficiency for glassware washers, is part of Section 7: Laboratory and Medical
Equipment. The complete list of best management practices is available at
www.epa.gov/watersense/best-management-practices. WaterSense has also developed
worksheets to assist with water management planningand case studies that highlight
successful water efficiency efforts of building owners and facility managers throughout the
country, available at www.epa.gov/watersense/commercial-buildings.

•	Section 1. Getting Started With Water Management

•	Section 2. Water Use Monitoring

•	Section 3. Sanitary Fixtures and Equipment

•	Section 4. Commercial Kitchen Equipment

•	Section 5. Outdoor Water Use

•	Section 6. Mechanical Systems

•	Section 7. Laboratory and Medical Equipment

•	Section 8. Onsite Alternative Water Sources

EPA 832-F-23-003
Office of Water

U.S. Environmental Protection Agency
March 2024

This document is one section from WaterSense at Work: Best Management Practices for Commercial and
Institutional Facilities (EPA-832-F-23-003). Other sections can be downloaded from

vwwv.epa.gov/watersense/best-management-practices. Sections will be reviewed and periodically updated
to reflect new information. The work was supported under contract 68HERC20D0026 with Eastern Research
Group, Inc. (ERG).

March 2024

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Laboratory and Medical Equipment
Glassware Washers

WaterSense

Overview

Glassware washers are automated
washing devices that remove chemical
or other particle buildup on laboratory
glassware, such as pipettes, flasks, and
graduated cylinders. Glassware
washers are often supplied with both
potable and purified water (e.g.,
deionized [Dl] water or reverse osmosis
[RO] permeate). Purified water is
typically used in the final rinse stages to
ensure that no contaminants are left on
glassware surfaces. Potable water used
duringother wash or rinse stages may
or may not be treated with a water
softenerto reduce water hardness, which can cause scale buildup or mineral
accumulation on glassware. Similarto steam sterilizers (discussed in more detail in
WaterSense at Work Section 7.3: Steam Sterilizers at www.epa.gov/watersense/best-
management-practices). some glassware washers that operate at high temperatures may
require additional potable water to cool hot water discharge to 140ฐF (60ฐC) or less.

Glassware washers are a more water-efficient method of washing when compared to hand
washing and rinsing of laboratory glassware. In fact, it can take about 20 gallons (76 liters)
of water to hand wash 30 pieces of labware, while usingan efficient glassware washer
uses 13 gallons (49 liters) or less.1

Newer, more efficient glassware washers use flow control and sensing capabilities to
reduce water use for each wash and rinse cycle. Some also offer flexible programming,
allowing the user to select the number of rinse cycles needed to achieve the desired level
of cleanliness. Glassware washers that allow users to choose the number of rinse cycles
or otherwise customize the washing and rinsing process can help reduce water use. In
addition to selecting models with these water-efficient features, lab managers can save
water by selecting a glassware washer size appropriate for research needs without
oversizing. Because water used in glassware washers is typically heated to high
temperatures, using less water will save energy, too.

1 Henderson, Jordan. September 2020. "Choosing the Right Glassware Washer."

www.labconco.com/articles/choosing-the-right-glassware-washer.

Laboratory glassware washer

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WaterSense at Work	Glassware Washers

Operation, Maintenance, and User Education

For optimum glassware washer efficiency, consider the following operation, maintenance,
and user education tips:

•	Only run glassware washers
when they are full. Fill each
glassware washer rack to
maximum capacity.

•	Operate the glassware washer
near or at the minimum flow
rate recommended by the
manufacturer.

•	If the number of rinse cycles
can be chosen, select as few
rinse cycles as possible,
considering the cleanliness
requirements of the glassware.

Train Staff for Efficient Use

To reduce the water use and operating costs from
glassware washers, ensure staff and researchers
are trained on water-efficient washing practices.
First, communicate that running full loads of a
glassware washer uses less water than hand
washing glassware. If the glassware washer allows
the user to select the number of rinse cycles,
encourage them to select as few rinse cycles as
possible, keeping in mind the desired level of
cleanliness. Selecting a delayed or scheduled start
time can allow glassware washing during off-peak
hours, which can reduce energy costs.

Retrofit Options

If appropriate given the intended use of the glassware, consider installing a water recycling
system that reuses rinse cycle wastewater as wash water in the next load. Some systems
are capable of treating rinse cycle wastewater before reusing it. Consider the level of water
quality needed before choosing a recycling option.

Consider other add-ons such as cooling reservoirs or heat recovery systems, which can
reduce water and/or energy use. If the glassware washer is discharging water at
temperatures higher than 140ฐF (60ฐC), cooling reservoirs (e.g., drain tanks) can be used to
cool down hot water discharge instead of using potable water for tempering. Heat recovery
systems use drain tanks to cool discharge water and recover the discharge's heat by
transferring it to incoming water used for the next cleaning cycle, thus reducing energy
required for hot water generation.

Replacement Options

When purchasing a new glassware washer or replacing an existing one, consider a
glassware washer's size and configuration (e.g., undercounter, free-standing), ensuring it
is large enough to accommodate the laboratory's needs while also requiring users to run
full loads. Compare similar models based on water and energy use and select the more
efficient option. Also, lookforthe following features:

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WaterSense at Work

Glassware Washers

• Cycle selection that allows users
to optimize rinse cycles for both
effective and efficient cleaning.

• Reuse of final rinse water as
wash water for the next load, if
appropriate.

• Water intake monitoringto
adjust the amount of water used
based on load size.

If the glassware washer will operate at temperatures higher than 140ฐF (60ฐC), consider
glassware washers with a cooling reservoir and/or heat recovery system that eliminates
the need fortempering glassware washer discharge and can reduce energy consumption
needed for heating water in the next cleaning cycle.

Delayed or scheduled start
feature that allows the start time
to be scheduled during off-peak
hours to reduce energy costs.

Laboratory glassware washer

Savings Potential

Water savings can be achieved by replacing an existing glassware washer with a more
efficient one. A glassware washer's water use is dependent upon the amount of water used
during wash and rinse cycles, as well as the total number of cycles. A replacement
glassware washer can use less water per cycle through flow control and allow users to
select fewer cycles.

To estimate facility-specific water savings and payback, use the following information.
Current Water Use

To estimate the current water use of a glassware washer, identify the following information
and use Equation 1 on the next page:

•	Average volume of water used during a full wash process. This might be provided by
the product manufacturer through product literature or the manufacturer's website.
The water efficiency will be dependent upon the flow rate of each rinse or wash
cycle, duration of each cycle, and number of cycles. If the water use from the full
wash process is not available from the manufacturer, add up the water use from
each cycle to determine the water use from the full wash process.

•	Average number of wash processes per day.

•	Days of operation per year.

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WaterSense at Work

Glassware Washers

Equation 1. Water Use of Glassware Washer (gallons or liters per year)
= Wash Water Use x Wash Processes per Day x Days of Operation

Where:

•	Wash Water Use: Gallons (or liters) per wash

•	Wash Processes per Day: Washes per day

•	Days of Operation: Days of washer operation peryear

Water Use After Replacement

To estimate the water use of a more efficient replacement glassware washer, use Equation
1, substituting the average volume of water used during a full wash process of the
replacement glassware washer. Efficient models can use less than 13 gallons (49 liters)
during the full wash process.2 If the number of rinse cycles can be chosen, calculate the
maximum potential water savings using the water use corresponding to the fewest average
number of rinse cycles needed at the facility.

Water Savings

To calculate the water savings that can be achieved by replacing an existing glassware
washer, identify the following information and use Equation 2:

•	Current water use as calculated using Equation 1.

•	Water use after replacement as calculated using Equation 1.

Equation 2. Water Savings From Glassware Washer Replacement (gallons or liters per

year)

= Current Glassware Washer Water Use - Water Use After Glassware Washer

Replacement

Where:

•	Current Glassware Washer Water Use: Gallons (or liters) per
year

•	Water Use After Glassware Washer Replacement: Gallons (or
liters) peryear

2 Ibid.

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WaterSense at Work

Glassware Washers

Energy Savings

Because glassware washers use hot water, a reduction in water use will also result in
energy savings. The energy required to heat water can be dependent on the proportion of
water used in the glassware washer that is hot, fuel used for water heating (e.g., electricity,
natural gas), the efficiency of the water heater, and water heater temperature set points.
Since this information is not always readily available, energy savings that can be achieved
from replacing existing glassware washers can be estimated using the water savings
calculated in Equation 2 and the assumptions presented in Equation 3:

Equation 3. Energy Savings From Glassware Washer Replacement (kWh of electricity

or Mcf of natural gas per year)

= Water Savings (gallons or liters per year) x Average Percent of Water That Is Hot x
(Energy per Gallon or Liter Heated * Water Heater Efficiency)

Where:

•	Water Savings: Gallons (or liters) per year

•	Average Percent of Glassware Washer Water That Is Hot:
Facility-specific

•	Energy per Gallon or Liter Heated [assuming 75ฐF (24ฐC) water
temperature increase]:

o 0.183 kilowatt hours (kWh) of electricity per gallon

(0.048 kWh per liter); or
o 0.0006 Mcf (thousand cubic feet) of natural gas per
gallon (0.00016 Mcf per liter)

•	Water Heater Efficiency (unless otherwise known by the
facility):

o 1.0 for an electric hot water heater; or
o 0.75 for a natural gas hot water heater

Energy usage and costs can also be reduced by keeping a glassware washer in standby
mode when not in use and delaying the start of the wash cycle to during off-peak hours if
the glassware washer model has these programming capabilities.3

3 May, Mike. March 2019. "Going Green in Glassware Washing." www.labmanager.com/product-focus/going-
green-in-glassware-washing-1230.

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WaterSense at Work

Glassware Washers

Payback

To calculate the simple payback from the water savings associated with replacing an
existing glassware washer, consider the equipment and installation cost of the
replacement glassware washer, the water and energy savings as calculated using
Equation 2 and Equation 3, respectively, and the facility-specific cost of water,
wastewater, and energy.

Additional Resources

International Institute for Sustainable Laboratories (I2SL) and U.S. Environmental
Protection Agency (EPA). May 2022. Best Practices Guide: Water Efficiency in Laboratories.
www.epa.gov/system/files/documents/2022-06/ws-l2SL-Laboratory-Water-Efficiency-
Guide.pdf.

Lab Manager. Lab Glassware Washers Resource Guide, www.labmanager.com/lab-
glassware-washer-resource-guide-30393.

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Disclaimer

This document was prepared as an account of work sponsored by the United States Government.
While this document is believed to contain correct information, neither the United States
Government nor any agency thereof, nor any of their employees, makes any warranty, express or
implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any
information, apparatus, product, or process disclosed, or represents that its use would not infringe
privately owned rights. EPA hereby disclaims any liability for damages arising from the use of the
document, including, without limitation, direct, indirect or consequential damages including
personal injury, property loss, loss of revenue, loss of profit, loss of opportunity, or other loss.
Reference herein to any specific commercial product, process, or service by its trade name,
trademark, manufacturer, or otherwise does not necessarily constitute nor imply its endorsement,
recommendation, or favoring by the United States Government nor any agency thereof. The views
and opinions of authors expressed herein do not necessarily state or reflect those of the United
States Government nor any agency thereof.

c,EPA

United States Environmental Protection Agency
(4204M)

EPA 832-F-23-003
March 2024
vwwv.epa.gov/watersense
(866) WTR-SENS (987-7367)


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