What Is a Saran Gas Sampling Bag Used For? A Guide from Analytical Specialties
A Saran gas sampling bag from Analytical Specialties collects, transports, and stores gas samples (Saran Gas Sampling Bags). It is also used to collect expired breath samples for lab analysis, transfer gas from pressurized containers to atmospheric pressure, ship non-toxic gas samples, and prepare gas mixtures.
What is a Saran gas sampling bag made of?
Analytical Specialties makes its Saran gas sampling bags from double weight, aged, 2 mil (0.002 inch) type 18-100 Saran film that is specially treated to minimize permeability (Saran Gas Sampling Bags). Saran film is based on polyvinylidene chloride (PVDC), a polymer whose defining property is low permeability to water vapor and gases (Britannica). The seams on each bag are electronically bonded for a gas-tight seal, and every bag ships with a TN6 tube fitting sealed into the edge (Saran Gas Sampling Bags). Other valve choices are available.
What is a Saran gas sampling bag used for?
Analytical Specialties lists five core uses for its Saran bags: collecting, transporting, and storing gas samples; collecting expired breath samples for lab analysis; transferring gas from pressurized containers for use at atmospheric pressure; shipping non-toxic gas samples; and preparing gas mixtures (Saran Gas Sampling Bags). More broadly, Analytical Specialties' sampling bags are used for breath gas analysis, VOC and trace gas analysis, gas and vapor analysis, trace contaminant monitoring for high-purity gases, outgassing testing on solid samples, and air and odor analysis, for buyers across specialty chemicals, contract testing labs, petrochemical labs, industrial hygiene, polymer testing, aerospace and government research labs, and university labs.
Can you collect breath samples in a Saran bag?
Yes. Analytical Specialties names breath sample collection among its standard uses for Saran bags, and the approach has independent support outside the company's own materials: a 1971 study in the AIHA Journal used Saran bags to collect breath samples ahead of gas chromatographic analysis (AIHA Journal, 1971).
Can you ship gas samples in a Saran bag?
Yes, for non-toxic gas samples. Analytical Specialties lists "shipment of non-toxic gas samples" as one of the bag's intended uses (Saran Gas Sampling Bags). Filled bags with non-toxic samples can be shipped via UPS or other shipping services if necessary.
How permeable is a Saran gas sampling bag?
| Gas | Transmission rate (1 atm, 73.4°F, 1 mil film) |
|---|---|
| Oxygen | 0.8 to 1.1 cc/100 sq in/24 h |
| Carbon dioxide | 3.8 to 6.0 cc/100 sq in/24 h |
| Nitrogen | 0.12 to 0.16 cc/100 sq in/24 h |
| Air | 0.21 to 0.44 cc/100 sq in/24 h |
| Water vapor | 0.020 g/100 sq in/24 h at 75°F; 0.20 g/100 sq in/24 h at 100°F |
A lower transmission rate means less gas escapes through the film during storage. These figures are published for 1 mil film and are independently matched by a third-party barrier film reference chart (Sorbent Systems). Analytical Specialties' Saran bags are made from 2 mil film, twice the thickness of the film in the table above (Saran Gas Sampling Bags).
Saran, Tedlar, Kynar or Teflon: when is Saran the right choice?
When cost is a concern, Saran bags are a more economical choice. Saran (PVDC) film is non-reactive to most hydrocarbon analytes.
| Film | Smallest bag (6"x6") price | Key property | Product page |
|---|---|---|---|
| Saran | $11.60 | Chemically inert and disposable; Analytical Specialties describes it as "as chemically inert as Teflon bags but offer reduced permeability" | Saran |
| Tedlar | $17.35 | Rated for continuous use up to 225°F with appropriately rated fittings | Tedlar |
| Kynar (PVDF) | $13.05 | 3 mil film for ambient emission sampling; a 4 mil version is preconditioned to 45 to 65 ppb background for automotive emission sampling | Kynar |
| Teflon (FEP) | $21.90 | The most inert material Analytical Specialties offers; its main drawbacks are permeability and cost | Teflon |
Of the four films, Saran has the lowest listed price for a 6 inch by 6 inch bag, at $11.60, and Analytical Specialties recommends it for one-time use (Saran Gas Sampling Bags).
Which fitting comes on a Saran gas sampling bag?
The standard fitting is a TN6 tube fitting sealed into the edge of the bag, with a removable sleeve-type red rubber septum at each inlet (Saran Gas Sampling Bags). TN6 stands for Tube Septum Nylon, 3/8 inch, and a single bag can carry up to five fittings positioned anywhere on the bag (Fittings for Sampling Bags). Additional tubes can be added for flow-through sampling. Optional upgrades include a patented on-off septum fitting in Kynar or polypropylene, a stainless steel on-off zero-headspace fitting, a flush-mount 800-series fitting, and Halkey Roberts on-off, Jaco union, or Teflon septum fittings (Fittings for Sampling Bags).
Can you reuse a Saran gas sampling bag?
A Saran bag can be reused, but Analytical Specialties recommends one-time use, because the inside of any sampling bag is difficult to clean thoroughly and the low cost of a Saran bag makes single-use practical (Saran Gas Sampling Bags).
How long can you store a sample in a Saran gas sampling bag?
Samples have been stored in Saran bags from one day to several months, depending on the application.
What sizes do Saran gas sampling bags come in, and what do they cost?
| Size | Model | Capacity | Price |
|---|---|---|---|
| 6" x 6" | AS4350 | 0.5 L | $11.60 |
| 6" x 12" | AS4351 | 1.3 L | $13.75 |
| 8" x 12" | AS4352 | 2.0 L | $15.70 |
| 12" x 12" | AS4353 | 4.8 L | $18.20 |
| 12" x 24" | AS4354 | 12.0 L | $21.50 |
| 24" x 48" | AS4355 | 96.0 L | $53.85 |
Standard sizes run from 0.5 liter up to 24 inches by 96 inches, and Analytical Specialties also builds Saran bags custom to specification (Saran Gas Sampling Bags). The published minimum order is $200.
Where can I buy Saran gas sampling bags?
Standard sizes and fittings are available directly from Analytical Specialties' Saran product page (Saran Gas Sampling Bags). Analytical Specialties, Inc., the survivor company of Anspec, Inc., has been in business for 41 years, and Anspec introduced its Saran sample bags in 1975. For custom sizes, custom fittings, or larger orders, contact Analytical Specialties at sales@analyticalspecialties.com or (630) 578-6731, and specify the fitting type up front since fittings can be positioned anywhere on the bag.
Frequently asked questions
What is Saran film made from?
Saran film is based on polyvinylidene chloride (PVDC), a polymer known for low permeability to water vapor and gases (Britannica).
Is a Saran gas sampling bag chemically inert?
Analytical Specialties describes its Saran bags as "as chemically inert as Teflon bags but offer reduced permeability," a claim made by the company about its own product (Saran Gas Sampling Bags).
How is a Saran bag different from a Tedlar bag?
Saran is positioned as a lower-cost, one-time-use option, while Tedlar can be reused with nitrogen purging and is rated for continuous use up to 225°F (Tedlar Sampling Bags).
Can a Saran gas sampling bag be reused?
It can be, but Analytical Specialties recommends one-time use, since the inside of any sampling bag is hard to clean thoroughly (Saran Gas Sampling Bags).
What fitting comes standard on a Saran bag?
A TN6 tube fitting sealed into the edge of the bag, with a removable red rubber septum sleeve at each inlet (Saran Gas Sampling Bags).
What is the minimum order for a custom Saran gas sampling bag?
The published minimum order is $200.
Ready to order? Get standard Saran bag sizes directly from the Saran Gas Sampling Bags page, or call (630) 578-6731 or email sales@analyticalspecialties.com for custom sizes and fittings.
