WatchGas SST4-MICRO Diffusion 4-Gas Detector
Description
Every confined-space entry starts with the same four questions: enough O2, no combustibles at the LEL, no CO, no H2S. All four have to be right, every entry, every shift.
Entry teams in oil & gas, refining, wastewater, mining, and industrial contracting run this checklist dozens of times a week. Juggling two or three single-gas monitors on a belt — different alarm sounds, different bump schedules, different batteries dying at different times — is how the small errors accumulate.
The WatchGas SST4-MICRO reads all four confined-space gases continuously — one instrument, one battery, one alarm pattern to trust, for a full 48-hour shift.
One instrument. Configurable low, high, TWA, and STEL alarms tuned to OSHA confined-space thresholds under 29 CFR 1910.146 (19.5% and 23.5% O2, 10% LEL, and toxic-gas setpoints for CO or SO2 plus H2S). Audible (95 dB at 30 cm), visual, and vibration alarms — you feel the SST4-MICRO in a noisy compressor room. The fastest T90 in its class means the alarm fires before the atmosphere shifts around you, not after. Largest LCD in the category — readable at arm's length in dim confined spaces. Near Field Communication for phone-based configuration. Wireless charging drops it onto an induction pad — no cable failures at the connector.
Why safety managers and entry-team leads standardize on the SST4-MICRO:
- Single-instrument answer to the standard four confined-space atmospheric hazards under 29 CFR 1910.146
- Choice of CO or SO2 on the fourth channel — CO for petrochemical, refining, generator, and indoor-combustion work; SO2 for pulp, paper, smelter, and ore-roasting operations
- Low Power Catalytic (LPC) LEL sensor — longer service life than legacy pellistor designs, at lower power draw
- 48-hour battery life on a single charge — full shift plus overnight rest
- 2-year warranty on the SST4 platform
- Bump test and calibration compatible with the
WatchGas SST-DOCK for fleet management — wireless-charging pad and bump/cal workflow in one docking session
- NFC configuration from a mobile device — no button sequence memorization
- Datalogging for compliance audits — OSHA 29 CFR 1910.146 permit-required confined space, and internal safety programs
PK Safety services the full WatchGas SST line with factory-trained technicians in-house. We also handle BW/Honeywell (Factory Authorized), RKI, and RAE Systems monitors — one shop for a mixed fleet. If a sensor drifts or reaches end-of-life, send the unit to us — you're not shipping equipment into a black box. Call us at
800.829.9580 to talk through the SST4-MICRO setup with someone who actually understands confined-space entry and the WatchGas SST platform.
This is right for you if:
- You perform permit-required confined-space entries under 29 CFR 1910.146 (tanks, vaults, sewers, boilers, silos, shafts, treatment cells)
- You need a single instrument that covers the four standard confined-space atmospheric hazards
- Your industry needs CO on the fourth channel (petrochemical, refining, generator ops, indoor combustion) OR SO2 (pulp, paper, smelter, ore roasting)
- You want NFC configuration, wireless charging, and SST-DOCK compatibility for fleet lifecycle management
- You're standardizing your entry-team fleet on one instrument type across a mixed-brand shop
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Numbers:
WG01-SST4-MICRO-X1OMH-Y — LPC / O2 / CO / H2S (filtered), Low Power Cat Bead
WG01-SST4-MICRO-X1OSH-Y — LPC / O2 / SO2 / H2S (filtered LEL Sensor), Low Power Cat Bead
Frequently Asked Questions
What are the standard alarm setpoints for a confined-space 4-gas monitor?
Under OSHA's permit-required confined-space entry standard (29 CFR 1910.146), the atmosphere is classified oxygen-deficient below 19.5% O2 and oxygen-enriched above 23.5% O2. For combustible gases, entry is prohibited when concentrations exceed 10% of the lower explosive limit (LEL). Toxic-gas alarm thresholds are set below OSHA's permissible exposure limits — for H2S, the OSHA ceiling is 20 ppm (29 CFR 1910.1000 Table Z-2); for CO, the 8-hour PEL is 50 ppm.
The SST4-MICRO ships with configurable low, high, TWA, and STEL setpoints for each gas, so you can tune to OSHA compliance levels, ACGIH TLVs, or a stricter internal standard. Factory-set alarm points are documented in the specification sheet.
When do I need a 4-gas monitor versus a single-gas monitor?
Permit-required confined-space entries under 29 CFR 1910.146 require testing for oxygen concentration, combustible gases, and toxic gases before and during entry. A 4-gas monitor covers all three atmospheric categories in a single instrument — O2, LEL (combustibles), and two toxic gases (H2S plus either CO or SO2 depending on the model). If your work involves confined-space entry, you need at least the four-gas set on hand.
Single-gas monitors are for continuous personal exposure monitoring for one specific hazard (like a shift-long H2S monitor on a sour-oil site) — they complement but do not replace a 4-gas for entry testing. Many operators pair a 4-gas SST4-MICRO for entry with a single-gas SST1 series monitor for continuous shift-length exposure tracking.
What's the difference between LPC, catalytic bead, and NDIR LEL sensors?
All three detect combustible gases, with different tradeoffs. Traditional catalytic bead (pellistor) sensors have been the confined-space standard for decades but are susceptible to sensor poisoning (silicone, sulfur, tetraethyl lead) and drift over time. Low Power Catalytic (LPC) — used in the SST4-MICRO — is a modern refinement of the catalytic principle with longer service life, better poisoning resistance, and lower power draw. NDIR (Non-Dispersive Infrared) sensors don't require oxygen to detect combustibles and don't suffer from catalytic poisoning, but they respond to methane and heavier hydrocarbons at different sensitivities and cost more.
LPC is the mainstream choice for oil & gas and general confined-space work. If your entries are in inerted atmospheres (nitrogen, CO2 blankets) where oxygen is intentionally displaced, NDIR is worth considering — the SST4-PUMP and SST4-MINI offer NDIR-LEL sensor options for that use case.
How often should I bump test and calibrate the SST4-MICRO?
Bump test before every use — a quick check with a known gas concentration that confirms the sensor responds and the alarms fire. Calibration is a longer procedure that adjusts sensor readings against a certified gas concentration standard. Manufacturer recommendation for the SST4 platform is calibration every six months at minimum; many operators calibrate quarterly or after any alarm event.
The
WatchGas SST-DOCK automates both bump test and calibration in about 60 seconds per unit and logs everything for compliance audits under 29 CFR 1910.146 recordkeeping requirements.
Does the SST4-MICRO work with the WatchGas SST-DOCK docking station?
Yes. The SST4-MICRO is fully compatible with the
WatchGas SST-DOCK Touchscreen docking station for bump testing, calibration, and datalogging. If you're running a fleet of SST4-MICRO monitors, the SST-DOCK automates the compliance workflow with timestamped logs suitable for OSHA audits.
The wireless-charging pad on the SST-DOCK connects to the SST4-MICRO with no cable connectors — one docking session covers bump test, calibration, log upload, and battery charge in a single hands-off workflow.
How does PK Safety support the SST4-MICRO after purchase?
PK Safety carries the full WatchGas SST line and services the SST4-MICRO with factory-trained technicians in-house. That covers sensor replacement, calibration, firmware updates, and warranty support. Call
800.829.9580 to talk through your confined-space entry program with someone who knows the SST4 platform and understands the entry work — not a call-center script.
PK Safety also handles BW/Honeywell (Factory Authorized), RKI, and RAE Systems monitors under the same roof, so a mixed-brand fleet doesn't mean shipping to multiple service centers.
Not sure the SST4-MICRO is the right fit for your entry program? Call PK Safety at 800.829.9580. A person who knows confined-space entry and the WatchGas SST platform will pick up.
Read more
Description
Every confined-space entry starts with the same four questions: enough O2, no combustibles at the LEL, no CO, no H2S. All four have to be right, every entry, every shift.
Entry teams in oil & gas, refining, wastewater, mining, and industrial contracting run this checklist dozens of times a week. Juggling two or three single-gas monitors on a belt — different alarm sounds, different bump schedules, different batteries dying at different times — is how the small errors accumulate.
The WatchGas SST4-MICRO reads all four confined-space gases continuously — one instrument, one battery, one alarm pattern to trust, for a full 48-hour shift.
One instrument. Configurable low, high, TWA, and STEL alarms tuned to OSHA confined-space thresholds under 29 CFR 1910.146 (19.5% and 23.5% O2, 10% LEL, and toxic-gas setpoints for CO or SO2 plus H2S). Audible (95 dB at 30 cm), visual, and vibration alarms — you feel the SST4-MICRO in a noisy compressor room. The fastest T90 in its class means the alarm fires before the atmosphere shifts around you, not after. Largest LCD in the category — readable at arm's length in dim confined spaces. Near Field Communication for phone-based configuration. Wireless charging drops it onto an induction pad — no cable failures at the connector.
Why safety managers and entry-team leads standardize on the SST4-MICRO:
- Single-instrument answer to the standard four confined-space atmospheric hazards under 29 CFR 1910.146
- Choice of CO or SO2 on the fourth channel — CO for petrochemical, refining, generator, and indoor-combustion work; SO2 for pulp, paper, smelter, and ore-roasting operations
- Low Power Catalytic (LPC) LEL sensor — longer service life than legacy pellistor designs, at lower power draw
- 48-hour battery life on a single charge — full shift plus overnight rest
- 2-year warranty on the SST4 platform
- Bump test and calibration compatible with the WatchGas SST-DOCK for fleet management — wireless-charging pad and bump/cal workflow in one docking session
- NFC configuration from a mobile device — no button sequence memorization
- Datalogging for compliance audits — OSHA 29 CFR 1910.146 permit-required confined space, and internal safety programs
PK Safety services the full WatchGas SST line with factory-trained technicians in-house. We also handle BW/Honeywell (Factory Authorized), RKI, and RAE Systems monitors — one shop for a mixed fleet. If a sensor drifts or reaches end-of-life, send the unit to us — you're not shipping equipment into a black box. Call us at 800.829.9580 to talk through the SST4-MICRO setup with someone who actually understands confined-space entry and the WatchGas SST platform.
This is right for you if:
- You perform permit-required confined-space entries under 29 CFR 1910.146 (tanks, vaults, sewers, boilers, silos, shafts, treatment cells)
- You need a single instrument that covers the four standard confined-space atmospheric hazards
- Your industry needs CO on the fourth channel (petrochemical, refining, generator ops, indoor combustion) OR SO2 (pulp, paper, smelter, ore roasting)
- You want NFC configuration, wireless charging, and SST-DOCK compatibility for fleet lifecycle management
- You're standardizing your entry-team fleet on one instrument type across a mixed-brand shop
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Numbers:
WG01-SST4-MICRO-X1OMH-Y — LPC / O2 / CO / H2S (filtered), Low Power Cat Bead
WG01-SST4-MICRO-X1OSH-Y — LPC / O2 / SO2 / H2S (filtered LEL Sensor), Low Power Cat Bead
Frequently Asked Questions
What are the standard alarm setpoints for a confined-space 4-gas monitor?
Under OSHA's permit-required confined-space entry standard (29 CFR 1910.146), the atmosphere is classified oxygen-deficient below 19.5% O2 and oxygen-enriched above 23.5% O2. For combustible gases, entry is prohibited when concentrations exceed 10% of the lower explosive limit (LEL). Toxic-gas alarm thresholds are set below OSHA's permissible exposure limits — for H2S, the OSHA ceiling is 20 ppm (29 CFR 1910.1000 Table Z-2); for CO, the 8-hour PEL is 50 ppm.
The SST4-MICRO ships with configurable low, high, TWA, and STEL setpoints for each gas, so you can tune to OSHA compliance levels, ACGIH TLVs, or a stricter internal standard. Factory-set alarm points are documented in the specification sheet.
When do I need a 4-gas monitor versus a single-gas monitor?
Permit-required confined-space entries under 29 CFR 1910.146 require testing for oxygen concentration, combustible gases, and toxic gases before and during entry. A 4-gas monitor covers all three atmospheric categories in a single instrument — O2, LEL (combustibles), and two toxic gases (H2S plus either CO or SO2 depending on the model). If your work involves confined-space entry, you need at least the four-gas set on hand.
Single-gas monitors are for continuous personal exposure monitoring for one specific hazard (like a shift-long H2S monitor on a sour-oil site) — they complement but do not replace a 4-gas for entry testing. Many operators pair a 4-gas SST4-MICRO for entry with a single-gas SST1 series monitor for continuous shift-length exposure tracking.
What's the difference between LPC, catalytic bead, and NDIR LEL sensors?
All three detect combustible gases, with different tradeoffs. Traditional catalytic bead (pellistor) sensors have been the confined-space standard for decades but are susceptible to sensor poisoning (silicone, sulfur, tetraethyl lead) and drift over time. Low Power Catalytic (LPC) — used in the SST4-MICRO — is a modern refinement of the catalytic principle with longer service life, better poisoning resistance, and lower power draw. NDIR (Non-Dispersive Infrared) sensors don't require oxygen to detect combustibles and don't suffer from catalytic poisoning, but they respond to methane and heavier hydrocarbons at different sensitivities and cost more.
LPC is the mainstream choice for oil & gas and general confined-space work. If your entries are in inerted atmospheres (nitrogen, CO2 blankets) where oxygen is intentionally displaced, NDIR is worth considering — the SST4-PUMP and SST4-MINI offer NDIR-LEL sensor options for that use case.
How often should I bump test and calibrate the SST4-MICRO?
Bump test before every use — a quick check with a known gas concentration that confirms the sensor responds and the alarms fire. Calibration is a longer procedure that adjusts sensor readings against a certified gas concentration standard. Manufacturer recommendation for the SST4 platform is calibration every six months at minimum; many operators calibrate quarterly or after any alarm event.
The WatchGas SST-DOCK automates both bump test and calibration in about 60 seconds per unit and logs everything for compliance audits under 29 CFR 1910.146 recordkeeping requirements.
Does the SST4-MICRO work with the WatchGas SST-DOCK docking station?
Yes. The SST4-MICRO is fully compatible with the WatchGas SST-DOCK Touchscreen docking station for bump testing, calibration, and datalogging. If you're running a fleet of SST4-MICRO monitors, the SST-DOCK automates the compliance workflow with timestamped logs suitable for OSHA audits.
The wireless-charging pad on the SST-DOCK connects to the SST4-MICRO with no cable connectors — one docking session covers bump test, calibration, log upload, and battery charge in a single hands-off workflow.
How does PK Safety support the SST4-MICRO after purchase?
PK Safety carries the full WatchGas SST line and services the SST4-MICRO with factory-trained technicians in-house. That covers sensor replacement, calibration, firmware updates, and warranty support. Call 800.829.9580 to talk through your confined-space entry program with someone who knows the SST4 platform and understands the entry work — not a call-center script.
PK Safety also handles BW/Honeywell (Factory Authorized), RKI, and RAE Systems monitors under the same roof, so a mixed-brand fleet doesn't mean shipping to multiple service centers.
Not sure the SST4-MICRO is the right fit for your entry program? Call PK Safety at 800.829.9580. A person who knows confined-space entry and the WatchGas SST platform will pick up.
Every confined-space entry starts with the same four questions: enough O2, no combustibles at the LEL, no CO, no H2S. All four have to be right, every entry, every shift.
Entry teams in oil & gas, refining, wastewater, mining, and industrial contracting run this checklist dozens of times a week. Juggling two or three single-gas monitors on a belt — different alarm sounds, different bump schedules, different batteries dying at different times — is how the small errors accumulate.
The WatchGas SST4-MICRO reads all four confined-space gases continuously — one instrument, one battery, one alarm pattern to trust, for a full 48-hour shift.
One instrument. Configurable low, high, TWA, and STEL alarms tuned to OSHA confined-space thresholds under 29 CFR 1910.146 (19.5% and 23.5% O2, 10% LEL, and toxic-gas setpoints for CO or SO2 plus H2S). Audible (95 dB at 30 cm), visual, and vibration alarms — you feel the SST4-MICRO in a noisy compressor room. The fastest T90 in its class means the alarm fires before the atmosphere shifts around you, not after. Largest LCD in the category — readable at arm's length in dim confined spaces. Near Field Communication for phone-based configuration. Wireless charging drops it onto an induction pad — no cable failures at the connector.
Why safety managers and entry-team leads standardize on the SST4-MICRO:
- Single-instrument answer to the standard four confined-space atmospheric hazards under 29 CFR 1910.146
- Choice of CO or SO2 on the fourth channel — CO for petrochemical, refining, generator, and indoor-combustion work; SO2 for pulp, paper, smelter, and ore-roasting operations
- Low Power Catalytic (LPC) LEL sensor — longer service life than legacy pellistor designs, at lower power draw
- 48-hour battery life on a single charge — full shift plus overnight rest
- 2-year warranty on the SST4 platform
- Bump test and calibration compatible with the WatchGas SST-DOCK for fleet management — wireless-charging pad and bump/cal workflow in one docking session
- NFC configuration from a mobile device — no button sequence memorization
- Datalogging for compliance audits — OSHA 29 CFR 1910.146 permit-required confined space, and internal safety programs
PK Safety services the full WatchGas SST line with factory-trained technicians in-house. We also handle BW/Honeywell (Factory Authorized), RKI, and RAE Systems monitors — one shop for a mixed fleet. If a sensor drifts or reaches end-of-life, send the unit to us — you're not shipping equipment into a black box. Call us at 800.829.9580 to talk through the SST4-MICRO setup with someone who actually understands confined-space entry and the WatchGas SST platform.
This is right for you if:
- You perform permit-required confined-space entries under 29 CFR 1910.146 (tanks, vaults, sewers, boilers, silos, shafts, treatment cells)
- You need a single instrument that covers the four standard confined-space atmospheric hazards
- Your industry needs CO on the fourth channel (petrochemical, refining, generator ops, indoor combustion) OR SO2 (pulp, paper, smelter, ore roasting)
- You want NFC configuration, wireless charging, and SST-DOCK compatibility for fleet lifecycle management
- You're standardizing your entry-team fleet on one instrument type across a mixed-brand shop
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Numbers:
WG01-SST4-MICRO-X1OMH-Y — LPC / O2 / CO / H2S (filtered), Low Power Cat Bead
WG01-SST4-MICRO-X1OSH-Y — LPC / O2 / SO2 / H2S (filtered LEL Sensor), Low Power Cat Bead
Frequently Asked Questions
What are the standard alarm setpoints for a confined-space 4-gas monitor?
Under OSHA's permit-required confined-space entry standard (29 CFR 1910.146), the atmosphere is classified oxygen-deficient below 19.5% O2 and oxygen-enriched above 23.5% O2. For combustible gases, entry is prohibited when concentrations exceed 10% of the lower explosive limit (LEL). Toxic-gas alarm thresholds are set below OSHA's permissible exposure limits — for H2S, the OSHA ceiling is 20 ppm (29 CFR 1910.1000 Table Z-2); for CO, the 8-hour PEL is 50 ppm.
The SST4-MICRO ships with configurable low, high, TWA, and STEL setpoints for each gas, so you can tune to OSHA compliance levels, ACGIH TLVs, or a stricter internal standard. Factory-set alarm points are documented in the specification sheet.
When do I need a 4-gas monitor versus a single-gas monitor?
Permit-required confined-space entries under 29 CFR 1910.146 require testing for oxygen concentration, combustible gases, and toxic gases before and during entry. A 4-gas monitor covers all three atmospheric categories in a single instrument — O2, LEL (combustibles), and two toxic gases (H2S plus either CO or SO2 depending on the model). If your work involves confined-space entry, you need at least the four-gas set on hand.
Single-gas monitors are for continuous personal exposure monitoring for one specific hazard (like a shift-long H2S monitor on a sour-oil site) — they complement but do not replace a 4-gas for entry testing. Many operators pair a 4-gas SST4-MICRO for entry with a single-gas SST1 series monitor for continuous shift-length exposure tracking.
What's the difference between LPC, catalytic bead, and NDIR LEL sensors?
All three detect combustible gases, with different tradeoffs. Traditional catalytic bead (pellistor) sensors have been the confined-space standard for decades but are susceptible to sensor poisoning (silicone, sulfur, tetraethyl lead) and drift over time. Low Power Catalytic (LPC) — used in the SST4-MICRO — is a modern refinement of the catalytic principle with longer service life, better poisoning resistance, and lower power draw. NDIR (Non-Dispersive Infrared) sensors don't require oxygen to detect combustibles and don't suffer from catalytic poisoning, but they respond to methane and heavier hydrocarbons at different sensitivities and cost more.
LPC is the mainstream choice for oil & gas and general confined-space work. If your entries are in inerted atmospheres (nitrogen, CO2 blankets) where oxygen is intentionally displaced, NDIR is worth considering — the SST4-PUMP and SST4-MINI offer NDIR-LEL sensor options for that use case.
How often should I bump test and calibrate the SST4-MICRO?
Bump test before every use — a quick check with a known gas concentration that confirms the sensor responds and the alarms fire. Calibration is a longer procedure that adjusts sensor readings against a certified gas concentration standard. Manufacturer recommendation for the SST4 platform is calibration every six months at minimum; many operators calibrate quarterly or after any alarm event.
The WatchGas SST-DOCK automates both bump test and calibration in about 60 seconds per unit and logs everything for compliance audits under 29 CFR 1910.146 recordkeeping requirements.
Does the SST4-MICRO work with the WatchGas SST-DOCK docking station?
Yes. The SST4-MICRO is fully compatible with the WatchGas SST-DOCK Touchscreen docking station for bump testing, calibration, and datalogging. If you're running a fleet of SST4-MICRO monitors, the SST-DOCK automates the compliance workflow with timestamped logs suitable for OSHA audits.
The wireless-charging pad on the SST-DOCK connects to the SST4-MICRO with no cable connectors — one docking session covers bump test, calibration, log upload, and battery charge in a single hands-off workflow.
How does PK Safety support the SST4-MICRO after purchase?
PK Safety carries the full WatchGas SST line and services the SST4-MICRO with factory-trained technicians in-house. That covers sensor replacement, calibration, firmware updates, and warranty support. Call 800.829.9580 to talk through your confined-space entry program with someone who knows the SST4 platform and understands the entry work — not a call-center script.
PK Safety also handles BW/Honeywell (Factory Authorized), RKI, and RAE Systems monitors under the same roof, so a mixed-brand fleet doesn't mean shipping to multiple service centers.
Not sure the SST4-MICRO is the right fit for your entry program? Call PK Safety at 800.829.9580. A person who knows confined-space entry and the WatchGas SST platform will pick up.
Specifications
Specifications
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