A Tedlar bag is a flexible gas grab sampler, and three choices decide whether the sample you collect is the sample your lab receives: the size (fill it to about 80% of its nominal volume, so a 10 L bag yields roughly 8 L), the film (Tedlar suits most VOCs but is the wrong film for methane, CO2 and long-term H2S storage) and the handling routine (light, hold time and shipping all change the result). This guide covers the Jensen Tedlar gas sampling bag ERE stocks in 18 sizes, when to choose a different film, and what EPA methods say about filling, light and hold time.
In this guide
- What is a Tedlar bag, and when is it the right sampler?
- Which Tedlar bag size do you need?
- Is Tedlar the right film for your target gas?
- Which valve and fitting should you use?
- How do you fill and handle a Tedlar bag without losing the sample?
- How long can a sample stay in a Tedlar bag?
- Can you reuse a Tedlar bag?
What Is a Tedlar Bag, and When Is It the Right Sampler?
A Tedlar bag is a sealed, flexible sample bag made from DuPont's polyvinyl fluoride (PVF) film, used to collect a gas sample in one go and carry it to an analyzer or lab. Use one for a grab or integrated sample of a gas that is stable in the film, not for a time-weighted exposure average, which is a job for a pump with a sorbent tube or cassette.
EPA writes bag sampling into its source-testing methods. Method 18 covers measuring gaseous organic compound emissions by gas chromatography and includes an integrated bag-sampling procedure, and SW-846 Method 0040 is built around collecting combustion-source VOCs in evacuated Tedlar bags. Both are US EPA methods, so confirm which method your Canadian approval, permit or lab procedure actually references.
Jensen's product sheet, hosted by ERE, lists the everyday jobs: assessing exposure from spills and leaks, biogas and landfill sampling (film matters for those gases, see below), calibration-gas standards and gas blending, grab sampling and peak concentrations, indoor air, vent sampling, soil gas and hazardous-waste-site sampling. If your question is instead "what is the concentration right now", a direct-reading instrument or gas detection tube may answer it without a bag; for landfill and biogas work, see our landfill gas monitoring guide.
Which Tedlar Bag Size Do You Need?
Divide the sample volume your lab or analyzer needs by 0.8 and choose the next size up. EPA Method 18 sets the final volume at approximately 80 percent of the bag's capacity, Jensen's guidance says not to fill beyond 80% of maximum volume, and Method 0040 warns that overfilling can burst the bag. The nominal size on the label is therefore not the sample volume you get.
Worked example: a lab asks for 3 L. 3 ÷ 0.8 = 3.75 L, so the 3 L bag is too small and the 5 L bag is the right choice, giving 4 L at 80% fill.
| Bag capacity | Usable sample at 80% fill | Sold in packs of |
|---|---|---|
| 0.6 L | 0.48 L | 10 |
| 1 L | 0.8 L | 10 |
| 1.2 L | 0.96 L | 10 |
| 2 L | 1.6 L | 10 |
| 3 L | 2.4 L | 10 |
| 5 L | 4 L | 10 |
| 7 L | 5.6 L | 10 |
| 8 L | 6.4 L | 10 |
| 9.5 L | 7.6 L | 10 |
| 10 L | 8 L | 10 |
| 12 L | 9.6 L | 5 |
| 16 L | 12.8 L | 5 |
| 25 L | 20 L | 5 |
| 40 L | 32 L | 5 |
| 56 L | 44.8 L | 3 |
| 73 L | 58.4 L | 3 |
| 80 L | 64 L | 3 |
| 100 L | 80 L | 3 |
All 18 sizes use a 3/16 in. O.D. stem, and the pack quantities above come from ERE's product record. Replacement septa are sold separately in packs of 10. Request pricing for the size you need from the Tedlar bag product page or the quote link at the end of this guide.
Is Tedlar the Right Film for Your Target Gas?
Tedlar is the right film for most VOC grab samples and the wrong one for methane, CO2 and long-term H2S storage. Jensen's guidance says low-molecular-weight gases such as methane, CO, CO2, hydrogen and inert gases are not stable in Tedlar, ALTEF or FEP, and that multi-layer foil is its best choice for H2S. The comparison below is condensed from the film comparison sheet ERE hosts on the product page.
| Film | Best for | Watch out for | Max temperature |
|---|---|---|---|
| Tedlar | Most VOC grab samples. Low gas permeation, high tensile strength (bags resist puncture in the field), less permeable and less expensive than FEP, PFA and TFM. | Background levels of DMAC and phenol; high CO2 permeation rate; relatively high O2 permeation rate. | 400°F (204°C) |
| ALTEF | Most VOCs and many sulfur compounds; low VOC background; no DMAC or phenol background. | More permeable than Tedlar to most compounds; not suitable for ketones and esters above 30%; many sulfur compounds must be analyzed within 24 hours; costs more than Tedlar. | 260°F (127°C) |
| Multi-layer foil | Methane, H2S, CO and CO2. The only bag material that adequately holds H2S for long periods; opaque; sample stability up to 5 days for most compounds. | Not recommended for low-ppm to high-ppb VOCs because of background from the bag material; analyze methane, H2S, CO and CO2 within 48 hours. | 190°F (88°C) |
| FEP | Extreme temperatures, corrosive gases and rough handling. | Poor long-term storage stability for most VOCs and sulfur compounds; much more permeable and more expensive than Tedlar; lower tensile strength. | 400°F (204°C) |
ERE stocks the Tedlar bag. If your target gas points to foil, ALTEF or FEP, Jensen makes those films too: send us the compound and the method reference and we will confirm what can be sourced.
Even inside Tedlar's comfort zone, some compounds do not survive storage. A 2010 study in Sensors by researchers at USDA-ARS, Iowa State University and other institutions put a standard gas of p-cresol and seven volatile fatty acids into commercial and homemade PVF bags. Average recoveries were about 16 to 18% at 1 hour and 2 to 5% at 7 days, and the authors recommended an alternative method such as sorbent tubes for accurate quantification of those compounds. The lesson is not that Tedlar fails everywhere; it is that stability is compound-specific, so check published bag-recovery data for your analyte, or run a spike recovery as Method 0040 requires, before choosing a bag over a pump and sorbent tube.
Which Valve and Fitting Should You Use?
The bag ERE stocks has a polypropylene screw-cap combo valve with a replaceable septum. It combines the on/off valve and the septum in a single unit, opens and closes with a quick-turn screw cap and shows at a glance whether it is open or closed. The septum is replaceable, which is why replacement septa are listed alongside the bags.
Two handling points come with the fitting. First, keep fluoropolymer tubing and fluoropolymer-faced septa in the sample path, because Jensen warns that other materials cause sample loss. Second, the film is rated for continuous use from -98°F to 400°F, but Jensen states the temperature limit depends on the fittings used, so check the valve before sampling hot gas.
Jensen's range includes other fittings: a nickel-plated barbed on/off valve, plastic Jaco and PFA fittings for tubing or septum, a Swagelok-type stainless steel fitting, and a stainless steel TCLP fitting designed for zero-headspace extractors. If your method calls for one of these, send us the method reference and we will confirm availability.
How Do You Fill and Handle a Tedlar Bag Without Losing the Sample?
Flush the bag, use inert tubing, fill to about 80%, keep the bag dark and get it to the lab inside its hold time. The steps below follow EPA Methods 18 and 0040 and Jensen's handling guidance; your method's own procedure takes precedence.
- Flush the bag before use. Flush the bag thoroughly with ultra-pure nitrogen or zero air. EPA Method 0040 notes that the bag material can contribute background hydrocarbons and that purging with air or nitrogen may reduce them.
- Leak-check the bag. Leak-check the bag and, if you fill it by evacuating a rigid container, the container as well. EPA Method 18 calls for both to be checked before sampling.
- Use fluoropolymer tubing and septa. Keep fluoropolymer tubing and fluoropolymer-faced septa in the sample path. Jensen warns that other materials cause sample loss.
- Fill to about 80% of capacity. Set the flow so the final volume is roughly 80% of the bag's nominal capacity, and check the bag as it fills so it is not overfilled and burst.
- Keep the bag out of light and cold. Hold the filled bag in a rigid, opaque container. Direct sunlight can raise background hydrocarbons from the bag, and temperatures below 0 °C can condense analytes (EPA Method 0040).
- Ship by ground and analyze promptly. Ship by ground transportation, follow hazardous-materials shipping rules, and have the sample analyzed within 72 hours (EPA SW-846 Method 0040), sooner for compounds known to be unstable.
If you fill by evacuating a rigid container, use a leakless, Teflon-coated diaphragm pump (or equivalent) and Teflon sample tubing, as Method 18 describes. For the pump side of the setup, see our Air Sampling collection.
How Long Can a Sample Stay in a Tedlar Bag?
Plan on analysis within 72 hours at most, and sooner for reactive or sticky compounds. EPA SW-846 Method 0040 requires bag samples to be analyzed within 72 hours of collection unless stability data show that significant (more than 20%) degradation does not occur over a longer period. The method also applies only to compounds whose loss from the bag stays under 20% over 72 hours in validation studies, demonstrated by spiking the analyte into inert gas in the laboratory and into stack gas in the field.
Other films have their own limits. In ERE's film comparison, methane, H2S, CO and CO2 in foil bags should be analyzed within 48 hours, and many sulfur compounds in ALTEF bags within 24 hours. Your lab's method or your regulator may set a tighter or different window, so confirm it before you sample.
Can You Reuse a Tedlar Bag?
Usually not for ambient air. Jensen's product sheet notes that the EPA does not recommend reusing sample bags for ambient air sampling, because previously sampled chemicals can adsorb onto the film and contaminate the next sample by off-gassing. Where reuse is unavoidable, clean the bag immediately by flushing and heating and store it with all air evacuated. Bags used for styrene or ethylbenzene cannot be reused, because cleaning and flushing will not completely remove them. If the result may be scrutinized, use a new bag.
For our full range, see the Gas Sampling Bags collection; pumps, cassettes and the rest of the sampling train are in the Air Sampling collection. If you are choosing between grab bags and time-weighted media, our guide to air sampling cassette types covers the particulate side.
Need help choosing a Tedlar bag?
ERE Inc. has been Canada's environmental equipment specialist for 30+ years. Tell us the target compound, the volume your lab needs and the method reference, and we will match the bag size, film and valve.
→ Request a Quote | 1-888-287-EREC | Browse Gas Sampling Bags | sales@ereinc.com
Frequently Asked Questions
How full should a Tedlar bag be filled?
About 80% of its nominal capacity. EPA Method 18 sets the final sample volume at approximately 80 percent of bag capacity, and Jensen's handling guidance says not to fill a bag beyond 80% of its maximum volume. A 10 L bag therefore delivers about 8 L of sample.
Is a Tedlar bag suitable for methane, CO2 or hydrogen sulfide?
Generally no. Jensen's guidance lists methane, CO, CO2, hydrogen and inert gases as not stable in Tedlar, and ERE's film comparison notes a high CO2 permeation rate for Tedlar and calls multi-layer foil the only bag material that holds H2S for long periods. Choose foil for those gases and analyze within 48 hours.
Can Tedlar bags be shipped by air?
Not unless the bags are stored in a pressurized area, according to Jensen's handling guidance. EPA Method 0040 specifies ground transportation for bag samples and says to follow hazardous-materials shipping procedures. Confirm the carrier's rules for your sample before shipping.
How long can a gas sample stay in a Tedlar bag?
Analyze it within 72 hours at most under EPA SW-846 Method 0040, unless stability data show less than 20% degradation over a longer period. Stability is compound-specific: a 2010 study found poor recoveries of some odorous compounds even at 1 hour, so confirm your analyte and your lab's own hold time.
Related articles
- Air Sampling Pumps: Buyer's Guide for Environmental & Occupational Hygiene Professionals in Canada
- Landfill Gas Monitoring Equipment: A Buyer's Guide for Canadian Facilities
- Gas Detection Tubes: A Buyer's Guide for Canada
- Air Sampling Cassette Types Compared: Air-O-Cell vs. Allergenco-D vs. Micro5 vs. PCM
Lire en français : Sacs d'échantillonnage de gaz Tedlar : comment choisir la bonne taille, le bon film et la bonne valve au Canada