Lab Manager Magazine's Independent Guide to Purchasing a Lab Water Purification System

What application are you using the water for? This is the first question you must answer when choosing a water purification system for your lab.

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There are many different features of a Water Purification Systems to take into consideration before making your purchase.Check out the latest water purification products here.

Primary Lab Use ASTM Type III

What is Your Expected Type III Lab Water Volume Usage?

This includes glassware washing, heating baths, filling autoclaves, feeding steam generators and environmental cabinets, hydroponics, or as a pre-treatment to Type I Lab Water Systems. If you choose “Primary Lab Use, ASTM Type III,” then you require a Type III Lab Water Purification System. Measured by ASTM standards specifications, Type III Lab Water will have a Resistivity @ 25 C (megohms-cm) of 4.00 and a Conductivity @ 25 C (micromhos/cm) of 0.250, the Total Organic Carbon (u/L) will measure under 200.

Next, let’s take a look at the volume of purified Type III Water you will need. This is a large factor to consider when choosing a Lab Water Purification System, as it is what separates many different price points of model lines for this purchase. With Type III water, specifically because of its common application of glassware washing and rinsing, you must pay attention to your peak volume usage of water during washing and rinsing cycles in your lab, as opposed to your average weekly use volume. The flow rate of Type III Lab Water is measured in Liters per Hour (L/hr). Make sure to add this to usage volume of multiple washing stations and all other purified dispensing points, as the Lab Water will stem from this primary source. Often, you will find that model numbers of the systems are named after the volume of water they produce.

System Volume

Based on your needs, you may choose either a moderate volume Type III system, which provides less than 30 L/hr or a large volume system providing more than 30 L/hr. You can check out the latest such systems at LabWrench.com. Each of these systems contain multiple methods of water purification, such as carbon cartridge filter, a reverse osmosis (RO) membrane and, often, a UV lamp. Ion exchange and distillation purification methods are also available.

General Lab Use, ASTM Type II

What is Your Expected Type II Lab Water Volume Usage?

Reagent make-up or dilution, buffer and media preparation, general chemistry, qualitative analysis, cell culture incubators, weatherometers, synthesis. If you chose “General Lab Use, ASTM Type II,” then you require a Type II Lab Water Purification System. Measured by ASTM standards specifications, Type II Lab Water will have a Resistivity @ 25 C (megohms-cm) of 1.00 and a Conductivity @ 25 C (microhos/cm) of 1.00, the Total Organic Carbons (u/L) will measure under 50.

Next, let’s take a look at the volume of purified Type II water you will need. This is a large factor to consider when choosing a Lab Water Purification System, as it is what separates many different price points of model lines for this purchase. The flow rate of Type II Lab Water is measured in Liters per Hour (L/hr). Average out your expected Type II Water use over a regular day and divide by 24 to get your desired Liters per Hour. Also keep in mind how likely, or unlikely, it is that all your stations would require Type II Water at a given time. Often, you will find that model numbers of the systems are named after the volume of water they produce.

Large Volume, Greater than 20 L/hr and Moderate Volume, less than 20 L/hr

There is one more selection criteria to consider for Type II Lab Water Systems that will help you narrow down your choices, and it comes back again to the application. Not all Type II Water Purification Systems are equal, as Type IIIs are. Some Type II systems exceed the water quality guidelines, making the water also acceptable for a broader range or higher-demanding applications. Water will be purified past the Type II standards using multiple purification methods in the same unit, such as a pre-treatment, deionization (DI), reverse osmosis (RO) membranes, distillation and, often, a UV lamp. This can produce Lab Water that is better than double distilled water quality.

Advanced use of Type II Lab Water can include applications such as flame atomic absorption, tissue and cell culture, cytology and histology preparations, electrophoresis, spectrophotometry, electrophysiology, electrochemistry and general purpose HPLC.

Basic use Type II Lab Water Systems that meet, but do not exceed the ASTM standard for water quality can be used for applications including a feed to Ultrapure Water systems, reagent make-up and dilution, buffer and media preparation and general chemistry.

Analytical Lab Use, ASTM Type I

HPLC Mobile Phase preparation, blanks and sample dilution for GC, HPLC, AA, ICP-MS, Molecular Biology, microbiology, PCR, electrophoresis, DNA sequencing, mammalian cell culture, in-vitro fertilization, antibody production and blotting. If you chose “Analytical Lab Use, ASTM Type I” then you require a Type I Lab Water Purification System, measured by ASTM standards specifications, Type I Lab Water will have a Resistivity @ 25 C (megohms-cm) of 18.2 and a Conductivity @ 25 C (microhos/cm) of 1.00, the Total Organic Carbons (u/L) will measure under 50. Type I Lab Water is often referred to as Ultrapure Lab Water.

First, let’s take a look at the volume of purified Type I water you will need, this is a large factor to consider when choosing a Lab Water Purification System as it is what separates many different price points of model lines for this purchase. Due to the small volume of usage requirements most labs have for Type I compared to Types II and III, the flow rate of Type I Lab Water is measured in Liters per Day (LPD).

One offshoot worth taking a look at are systems that produce UltraPure Type I Lab Water and Type II in high volume directly from one unit and directly from raw potable water that has not been pre-treated. You can find the latest of these systems and more at LabWrench.com

Greater than 50 Liters per Day

If you require over 50 Liters per Day of Type I Ultrapure Lab Water, you then need to take a closer look at the application for which you will be using the water. This is very important because your lab water needs to be polished using different purification techniques in order to eliminate the contaminents that are most troublesome to your particular application. The five primary Ultrapure Lab Water application groupings are General Lab, Analytical, Molecular Biology, Life Science and Elemental Analysis. However, there is also a sixth, and that is a Water Purification System that produces to spec ASTM Type I Water but does not contain many of the advanced features or application-specific purification techniques. This sixth grouping we will refer to as Economical. Since these systems are not often found to be application-specific, the can sit apart from the five application groups detailed below. The Economical group of Lab Water Purification Systems may suit your needs for some Type I uses.

The Five Application Groups:

  • Biological Grade uses for Type I Ultrapure Lab Water include monoclonal antibody production, DNA/RNA, endotoxin and nuclease-free water is required
  • General Analytical Lab uses for Type I Ultrapure Lab Water can include general chemistry, ICP-ES, IC, AAS, standard buffers, spectrophotometry, spectroscopy and chromatography applications such as UPLC, HPLC, GC or GFAA, GC/MS and ICP/MS.
  • Ultra Low TOC Analytical Lab uses for Type I Ultrapure Lab Water usually pertain to TOC analysis, electrochemistry, flameless AA and other applications where organic removal is essential, such as low-wavelength HPLC.
  • Ultra Low TOC Biological Grade uses for Type I Ultrapure Lab Water include cell and tissue culture, endotoxin analysis, immunology and protein purification. This is required whenever pyrogen, DNA/RNA, endotoxin and nuclease-free water is needed. These systems also have lower TOC; less than 3-5 PPB.

Less than 50 Liters per Day

If your lab has only a small volume requirement for Ultrapure Type I Lab Water, one more step will quickly direct you to a number of products that will suit your needs very well, eliminating the need to go through the next selection criteria and keeping your costs down. Before choosing a specific small volume system for your lab, you’ll need to identify the feed source of the water you will be sending to this system. Your choice depends on if you already use pre-purified water such as that from a Type II or Type III Lab Water Purification System or if you will be feeding raw potable water that has not been pre-purified by a Type II or III System.

Categories: Purchasing Guides

Published In

ReThinking Laboratory Safety Magazine Issue Cover
ReThinking Laboratory Safety

Published: June 1, 2009

Cover Story

Lab Safety Revisited

This month's cover story invites you to take a walk through your lab and look at everything as though seeing it for the first time, through unbiased eyes. Is there unnecessary clutter? Have your labcoats outlived their usefulness? What is the condition of your lab's extension cords? This simple exercise can help you develop a keener eye towards lab safety.