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From groundwater purging to vapor intrusion assessments, the tubing you choose can make or break sample quality, data accuracy, and even how smoothly your day goes in the field.
There are typically two criteria to go by when selecting the right tubing for the job:
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Material (compatibility, durability, chemical resistance, flexibility)
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Size (OD for fittings + routing, ID for flow and purge times)
This guide walks through the “why” behind the common tubing materials, including best applications for each kind, and how to avoid the classic sizing mistakes that lead to leaks, poor flow, or compatibility problems.
Why Material & OD Matter
Tubing choices look simple until you’re in the field with a line that won’t seal, won’t flow, or won’t hold up to what you’re putting through it. The fastest way to avoid those headaches is to decide on two things before you ever pick a specific part number: material and outside diameter (OD).
Material determines how the tubing behaves in the real world, what it can handle, how flexible it is, and whether it’s appropriate for sensitive sampling. OD determines whether it physically fits your fittings, ports, and hardware (note: some devices do require specific ID as well, so be sure and check that). Get those two right first, and everything else becomes a straightforward sizing decision.
1) Material
Material impacts:
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Chemical compatibility (what it can safely carry or be exposed to)
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Temperature tolerance
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Permeability (how likely it is to allow vapors/gases to pass through the wall)
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Flexibility/bend radius
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Burst strength/pressure performance
Flexible tubing is designed with the environmental industry in mind, and brands like ESP provide tubing made without forever chemicals such as PFOAS, while still being rated for industrial use or higher.
2) Outside Diameter (OD)
OD is often the make-or-break dimension because:
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Compression fittings and connectors commonly reference OD
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Passing tubing through ports, seals, and wellhead components is usually OD-limited
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OD consistency is what keeps assemblies predictable across brands and setups
Diameter basics: ID vs OD
If you’ve ever ordered tubing that looked right but didn’t fit your compression fittings, consider this:
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OD (Outside Diameter) is what most fittings care about. If your connection point is sized for 1/4" OD, you need tubing with 1/4" OD, regardless of ID.
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ID (Inside Diameter) influences flow (how fast you can purge) and can affect pressure drop. Some fittings are barbed and may reference the ID to insure a secure connection.
When you already know your required OD, consider a go-to shortcut like ESP’s Sort Tubing By Size (OD) page. It groups different materials that share the same OD, so you can compare cost and performance.
Tubing Material Breakdown: 8 Best Options
Below are the most common tubing materials for environmental applications – including groundwater sampling, soil vapor and gas sampling, intrusion assessments, and more.
FEP Teflon Tubing
The go-to for chemical resistance and sample integrity.
FEP Teflon (Fluoroethylenepropylene Teflon) is versatile and highly resistant to chemicals (including acids, bases, and organic solvents), with high temperature capability up to 400°F (204°C) and excellent electrical insulation properties.
In environmental sampling specifically, FEP Teflon’s high-temperature threshold and resistance to chemicals and VOCs help prevent the tubing itself from affecting the test sample. Unlike PTFE (polytetrafluoroethylene), FEP does not contain PFAS or PFOA, and FEP is approved by the DTSC for all soil gas sampling. It is generally not used fro PFAS testing.
When to choose FEP Teflon
Choose FEP when you need:
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Strong chemical resistance (harsh VOCs, solvents, aggressive environments)
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High temperature headroom
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Lower risk of tubing interfering with sensitive vapor/soil gas samples
Example spec snapshot (what “good documentation” looks like)
When looking for FEP Teflon Tubing, prioritize the full spec set, ID/OD, wall thickness, maximum working pressure (often listed at a reference temperature like 72°F), and the operating temperature range. Having those details makes it easier to confirm fitment and predict performance before you get to the field.
Teflon-Lined Polyethylene Tubing
A smart hybrid for vapor work.
If you want to prioritize sample integrity but you’re looking for a cost-effective option, Teflon-lined polyethylene is a common compromise.
Teflon-lined poly tubing is an economical solution for soil gas and vapor intrusion sampling, with many favorable features.
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Operating temperature range from -25°F to 180°F
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Applications include groundwater monitoring, air sampling tubes, laboratory applications, and water processing
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FEP liner maintains the purity of the sample
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Low permeability
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Moisture absorption is nearly zero
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PFOA-Free
A common size used in the field is 1/4" ID x 3/8" OD
When to choose Teflon-lined LDPE
Pick it when you need:
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Better vapor performance than straight poly (lower permeability)
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A smooth path for sample purity (FEP liner) without going full “all-Teflon”
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Reasonable temperature handling for most field environments
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Less prone to pinching due to LDPE outer shield layer.
LDPE Tubing
The workhorse for general water movement and utility use.
Low-Density Polyethylene (LDPE) shows up everywhere in field kits because it’s straightforward, widely compatible, and available in many common sizes and coil lengths.
LDPE has multiple common ID/OD combinations and coil options (100’, 500’, 1000’, depending on size), including:
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.17" ID x 1/4" OD
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1/4" ID x 3/8" OD
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3/8" ID x 1/2" OD
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1/2" ID x 5/8" OD
When to choose LDPE
LDPE is a strong option when:
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You’re doing groundwater tasks where extreme chemical resistance isn’t the priority
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You want easy handling, easy replacement, and familiar sizing
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You’re optimizing for cost and simplicity in standard workflows
Pro tip: If your workflow depends on compression fittings, don’t guess OD; use an OD sorter and then pick the material.
Nylaflow / Nylon Tubing
Pressure performance + tight bend radius.
When the job calls for high burst strength, resilience, and tighter routing, nylon is the usual step up.
Nylaflow & Nylon Tubing is high-quality pressure tubing (Up to 2500 psi) , with common wall types:
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Type T (Thin Wall)
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Type H (Heavy Wall)
Performance traits that matter in the field include:
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Durability and resilience
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Small bend radius
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High burst strength
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A long-lasting alternative with superior burst strength compared to vinyl, ethylene, and urethane tubing
Nylon’s chemical resistance includes a smooth inner surface (low friction), abrasion resistance, and typical applications like airlines, grease lines, vacuum lines, and hydraulic lines.
When to choose Nylon / Nylaflow
Choose it when you need:
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More pressure confidence (pneumatic/hydraulic use cases)
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A tighter bend radius without kinking
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Clean, low-friction flow characteristics
Silicone
The go-to for peristaltic pumps and clean “splice” connections.
If your workflow includes surgical tubing for a peristaltic pump (or you need a short, flexible “bridge” between rigid lines), silicone tubing is typically the easiest win.
Where silicone shines
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Peristaltic pump tubing (consistent compression/rebound through the pump head)
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Splicing between different tubing materials or assemblies where you need a compliant, grippy connection
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Fast field fixes (cut-to-length options make this simple)
There are equivalencies to common Masterflex sizes (helpful when you’re replacing tubing in an existing pump setup), like L/S 15, L/S 24, and L/S 36 equivalents.
Quick selection tip
With silicone, you’re usually matching pump-head size or splice fit, not just your instrument fitting. If you’re planning to connect silicone into a larger tubing system, it’s still smart to start by confirming your target OD.
Stainless Steel
When you need maximum durability, rigid routing, and rock-solid connections.
Stainless steel tubing is the “set it and forget it” option when flexible tubing starts to feel like a liability. Because it’s rigid, it holds its shape, protects the line from kinks and abrasion, and stays exactly where you route it, ideal for permanent or semi-permanent installations, cleaner layouts inside enclosures, or anywhere you want a repeatable setup.
A common specification you’ll see is 316 stainless steel in standard OD/ID combinations (for example, 1/4" OD x 0.18" ID), often available in straight lengths with the option to cut to a custom length for cleaner builds.
Where stainless steel shines
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Rigid, tidy routing (straight runs, tight layouts, consistent geometry)
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Mechanical protection where soft tubing would kink, rub through, or get stepped on
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Clean compatibility with compression fittings (unions, tees, caps) and small inline valves designed around common ODs like 1/4"
Selection tip: design from the outside in
With stainless steel, OD is usually the “anchor spec” because it dictates what fittings and valves you can use. Once OD is locked, you can choose ID based on desired flow while keeping the assembly consistent across builds.
Bonded
A dual-line organization that deploys fast and stays neat.
Bonded tubing is essentially two tubing runs permanently paired side-by-side into one tidy bundle. It’s especially useful any time you need two lines traveling together, because it prevents line-crossing, speeds deployment, and makes take-down and re-coiling much easier than managing separate tubes.
You’ll commonly see bonded configurations built from LDPE in pairs like 1/4" OD + 1/4" OD (often color/natural) or 1/4" OD + 3/8" OD, with longer coil lengths suited to field deployment.
Where bonded tubing shines
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Two-line routing where both lines follow the same path (pneumatic runs, paired transfer lines, instrument feeds + returns)
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Faster setup (one bundle to handle instead of two loose lines)
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Cleaner troubleshooting: Paired lines stay together; color/natural pairings help identify “Line A vs Line B.”
Vinyl Tubing
The flexible, budget-friendly option for general-purpose transfer.
When people say “vinyl tubing,” they’re usually referring to PVC (polyvinyl chloride) tubing. In day-to-day field and shop workflows, it’s popular because it’s easy to handle, easy to cut, and cost-effective, especially when you need short runs for temporary routing, drainage, or general fluid transfer where maximum chemical resistance isn’t the priority.
That said, vinyl/PVC is typically the material you pick for utility rather than sample integrity. If you’re doing sensitive vapor/soil gas work (or handling aggressive solvents), you’ll usually step up to FEP Teflon, for chemical resistance, or Teflon-lined LDPE, for a lower-permeability hybrid instead.
Where vinyl/PVC shines
Vinyl/PVC tubing is a practical fit when you need:
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Quick, temporary connections (setups that change often)
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Simple water movement (rinse water, non-aggressive fluids)
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Clear line visibility (easy to see flow and bubbles in many vinyl options)
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Low-cost tubing for non-critical runs
Where to be cautious
Vinyl/PVC is usually not the first choice when:
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You’re sampling for VOCs or doing soil gas/vapor intrusion work (material permeability and potential interaction matter)
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You’re moving aggressive chemicals/solvents (chemical compatibility can become a limitation)
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You need high-pressure performance (nylon is typically a better choice for burst strength and pressure lines)
Selection tip: Treat each side as its own OD Requirement
Even though it handles like one piece, each line still has its own OD that must match the fittings or connectors on that side of the system. A quick way to avoid mismatch headaches is to decide what each line must connect to, lock those ODs, then choose the bonded pair that meets both requirements.
Common ODs & Their Applications
Outside diameter (OD) is what needs to match your connectors, compression fittings, and pass-through hardware. Here are a few common ODs and where they typically shine in environmental field workflows:
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1/4" OD: Ideal for soil gas and vapor sampling (common choice for vapor/soil gas setups where smaller diameter lines are preferred).
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3/8" OD: Good for groundwater sampling with moderate flow (a practical middle ground when you need more flow than 1/4" OD but don’t want the bulk of larger tubing).
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1/2" OD and up: Best for deep wells, high-volume purging, or strong suction setups where higher flow and reduced drawdown time matter more than compact routing.
Ultimately, building a tubing setup that works reliably comes down to two field-proof decisions: choosing the right material for the chemistry and conditions and locking in the OD so everything fits and seals the first time.
That’s where ESP's tubing lineup stands out. Our flexible tubing is designed with the environmental industry in mind, rated for industrial use or higher, with many food-grade material options – and it’s all been industry-tested for over a decade.