KOMYO RIKAGAKU North川-Type Nitric Acid Gas Detection Tube (Model 244U)

Overview

The KOMYO RIKAGAKU North川-Type Nitric Acid Gas Detection Tube (Model 244U) is a field-deployable, colorimetric gas sampling device engineered for rapid, on-site quantification of nitric acid (HNO₃) vapor in ambient air or workplace environments. Based on the established North川 (Kitagawa) principle—first developed in Japan in the 1940s—the tube utilizes a fixed-bed reagent system sealed within calibrated borosilicate glass. When drawn through the tube using the standardized AP-20 hand pump (100 mL stroke volume, ±5% volumetric accuracy), nitric acid gas reacts stoichiometrically with immobilized chemical reagents (typically p-phenylenediamine derivatives and acidic catalysts), producing a discrete, linear color front. The length of color development corresponds directly to concentration via pre-engraved calibration markings, traceable to JIS K 0311 (Japanese Industrial Standard for colorimetric gas detector tubes) and aligned with ISO 8573-6 for compressed air purity assessment where HNO₃ contamination is a concern.

Key Features

• Pre-calibrated single-use design ensures batch-specific metrological traceability to Japanese National Metrology Institute (NMIJ) reference standards.
• Linear color-development response over the specified range (0.5–5 mg/m³), validated under controlled humidity (30–70% RH) and temperature (15–35°C) per manufacturer’s test protocol.
• Borosilicate glass construction provides chemical inertness against HNO₃ corrosion and thermal stability during transport and storage (shelf life: 24 months from manufacture date when stored at ≤25°C, protected from light).
• Compatible exclusively with the AP-20 dual-stroke hand pump (sold separately), which delivers precise 100 mL draw volumes with mechanical stop and integrated flow-rate verification window.
• No power, software, or external instrumentation required—enabling immediate deployment in confined spaces, emergency response vehicles, or outdoor industrial perimeters.

Sample Compatibility & Compliance

The 244U tube is validated for use in non-condensing gaseous matrices including ambient air, exhaust ducts, and indoor workplace atmospheres. It is not intended for use in high-humidity (>80% RH) or particulate-laden streams without upstream filtration (e.g., PTFE membrane filter, 0.3 µm pore size). Performance complies with JIS K 0311 Annex B for precision (±15% repeatability at mid-range concentration) and meets functional equivalence requirements under OSHA 29 CFR 1910.120 (HAZWOPER) for qualitative/semi-quantitative field screening. While not GLP-certified as a standalone instrument, its use within documented SOPs satisfies preliminary assessment criteria under ISO/IEC 17025:2017 Clause 7.2.2 for method selection in environmental monitoring workflows.

Software & Data Management

As a passive, analog measurement system, the 244U detection tube does not interface with digital software or data acquisition platforms. Quantitative results are manually recorded by reading the color front position against the engraved scale (resolution: 0.5 mg/m³). For auditability, users are advised to document pump actuation count, ambient conditions, operator ID, and photographic evidence of the developed tube (per ISO 14001:2015 Clause 7.5.3 on record control). Digital log templates compatible with EPA Region 10 Field Sampling Guidance are available upon request from authorized KOMYO RIKAGAKU distributors.

Applications

• Routine industrial hygiene monitoring near nitric acid storage tanks, mixing stations, and metal etching lines.
• Emergency response triage following transportation incidents involving nitric acid cargo (e.g., DOT Class 8 Corrosive Material spills).
• Verification of local exhaust ventilation (LEV) effectiveness in semiconductor fabrication cleanrooms where HNO₃ is used in wafer cleaning baths.
• Compliance checks against Japan’s Air Pollution Control Act (APCA) emission limits for nitrogen oxides (NOₓ) conversion pathways yielding HNO₃ aerosol.
• Educational laboratory demonstrations of acid gas behavior and stoichiometric colorimetric reaction kinetics.

FAQ

Is the 244U tube certified for use in explosion-hazardous areas (ATEX/IECEx)?
No—this is a passive glass tube requiring manual pumping; it carries no intrinsic ignition risk but must be used outside classified zones when paired with non-sparking AP-20 pumps.
Can the tube be reused after partial development?
No—each tube is factory-sealed and designed for single-use only. Reuse invalidates calibration and introduces cross-contamination risk.
What is the uncertainty budget for a typical field measurement?
Total expanded uncertainty (k=2) is ±22% at 2.5 mg/m³, accounting for pump volume error (±5%), visual endpoint estimation (±10%), and batch calibration drift (±7%).
Does KOMYO provide NIST-traceable calibration certificates?
Yes—certificates of analysis (CoA) listing batch-specific calibration curves and NMIJ traceability are supplied with each case of 10 tubes.
How should expired tubes be disposed?
Tubes must be treated as hazardous chemical waste per local regulations (e.g., EPA D002 for corrosivity); glass and reagent residues require neutralization prior to landfill disposal.