Dosimeter Tubes TWA
GASTEC Dosi-Tubes Direct-Reading Passive Dosimeter Tubes
Passive. Wearable. Direct-Reading Workshift TWA Exposure.
GASTEC Dosi-Tubes are direct-reading passive dosimeter tubes engineered to monitor personal Time-Weighted Average (TWA) worker exposure to hazardous gases and chemical vapors over 1 to 8-hour work shifts. Relying purely on natural molecular gaseous diffusion across a precision diffusion path, they require zero sampling pumps, electrical power, or expensive post-sampling laboratory chromatography.
Pure Passive Gaseous Diffusion
Gas molecules diffuse naturally into the tube at a constant rate governed by Fick's first law of diffusion.
Zero Pump or Battery Expense
Eliminates pump calibration, charging docks, tubing snags, and motor noise completely.
Direct-Reading Calibrated Scales
Tubes feature clear ppm-hour or direct ppm scales printed on the glass body for immediate reading.
Full 8-Hour Workshift Protection
Continuously accumulates chemical exposure over normal 8-hour or extended 12-hour industrial shifts.
Personal Breathing Zone Monitoring
Clips effortlessly to a worker's collar or shirt pocket via the dedicated Dositube lapel holder.
ATEX Zone 0 Intrinsically Safe
Non-electrical glass construction is completely spark-free and safe in combustible atmospheres.
Wear & Read. 3 Steps to Personal Workplace Safety.
Snap Off Tube End
Use the included tip breaker to snap off only the intake scored tip of the Dosi-Tube to begin diffusion.
Clip to Breathing Zone
Place the tube inside the GASTEC Dositube holder and clip it securely to the worker's collar or lapel.
Read TWA Stain at Shift End
At the end of the shift, observe the color stain boundary on the printed scale and divide by total exposure hours.
Precision Diffusion Path
Calibrated air column length provides an exact, reproducible molecular diffusion cross-section.
Reagent Immobilization
High-purity chemical reagents react proportionally to create a sharp, distinct color demarcation line.
Immediate On-Site Compliance
Safety officers can immediately verify if worker exposure remained below OSHA or ACGIH TLV limits.
Chemical Manufacturing & Refineries
Measures worker 8-hour shift exposure to Ammonia, Hydrogen Sulfide, Sulfur Dioxide, and Chlorine.
Industrial Spray Painting & Coating
Monitors personal exposure to volatile aromatic solvents such as Toluene, Xylene, and Acetone.
Hospital Sterilization & Laboratories
Tracks worker exposure to toxic Ethylene Oxide, Formaldehyde, and anesthetic gas leakages.
Automotive & Aerospace Workshops
Evaluates degreasing, solvent cleaning, and parts washing stations for organic vapor compliance.
Agricultural Silos & Cold Storage
Monitors continuous worker exposure to ammonia refrigeration vapors and fumigation residues.
Wastewater Treatment Plants
Verifies daily H₂S exposure levels for operations personnel working around wet wells and headworks.
The Specs Speak for Themselves
Engineered advantages of GASTEC passive direct-reading dosimeter tubes.
Zero Lab Fees
provides immediate on-site results without waiting days for analytical laboratory GC results
1 to 8 Hours
flexible sampling exposure periods allow short-term task checks or full work-shift TWA logging
Fick's Law
molecular diffusion physics guarantees strict linearity without pump mechanical variability
GASTEC Dosi-Tubes Technical Specifications
Available gas types, measurement ranges, and operational guidelines.
| Specification Parameter | Details |
|---|---|
| Product Family | GASTEC Dosi-Tube Series (Direct-Reading Passive Tubes) |
| Measurement Principle | Passive gaseous molecular diffusion with colorimetric reaction |
| Sampling Duration | 1 to 8 hours (or extended 10–12 hour shifts) |
| Available Target Gases | Ammonia, CO, CO₂, Chlorine, Formaldehyde, H₂S, NO₂, SO₂, Toluene, Xylene, etc. |
| Reading Scale | Direct ppm or ppm-hours printed directly on tube glass |
| Power & Pump Requirements | None (completely passive) |
| Packaging Quantity | 10 tubes per box |
| Storage Conditions | Cool, dark place (refrigerated for select sensitive tube chemistries) |
| Applicable Holder | GASTEC Dositube Holder (No. 710) |
