WatchGas SST1 2 Year O2 Gas Detector SST1-O-24
Description
Not every O2 monitor needs to give you a percentage readout. Sometimes the job just needs a badge that alarms when the atmosphere isn't breathable — no calibration schedule, no battery replacement cycle, no training curve. That's what the SST1 Limited-Life line is for.
Oxygen depletion is the danger that hides in plain sight. The gases that displace O2 in industrial settings — nitrogen, argon, helium, carbon dioxide, methane — are colorless and odorless. Workers get no sensory warning that oxygen levels are falling. And unlike CO or H2S where symptoms give some warning, O2 depletion has a nasty physiology: cognitive impairment begins around 16% oxygen, workers stop recognizing they're in danger by ~12%, and unconsciousness can occur within minutes at 8%. The monitor is the only warning because the physiology itself impairs the judgment needed to notice.
The WatchGas SST1 2-Year O2 gas detector is an alert-only monitor: no digital percentage display, factory-set alarm setpoints anchored to OSHA's confined-space atmosphere classifications, non-serviceable, and no maintenance required. Activate it once, and it runs continuously for two years — no calibration, no battery replacement, no charging — alarming immediately when oxygen falls below 19.5% (deficient) or rises above 23.5% (enriched). At $150, it's the lowest-cost O2 monitor in the SST1 line — designed for jobs that finish inside two years.
Two ways to run O2 monitoring — pick the one that fits your job.
The SST1 O2 line covers both tiers:
-
Full-instrument, serviceable: the
WatchGas SST1-O serviceable O2 monitor — digital percentage readout, configurable low/high/TWA/STEL alarms, replaceable sensor cell at end-of-life, integration with the WatchGas SST platform. Higher upfront cost; lowest lifecycle cost when the monitor stays in service for years.
-
Limited-life, alert-only (this SKU): $150, no display, factory-set alarms at OSHA's confined-space thresholds, no maintenance for two years, discarded at end-of-life. Simpler operation; ideal for jobs where a full instrument is over-spec.
Factory-set alarm thresholds, anchored to OSHA's confined-space atmosphere classifications: Low 19.5% and High 23.5% match exactly to OSHA's regulatory definitions under 29 CFR 1910.146 — the Permit-Required Confined Spaces standard. Below 19.5% is classified as an oxygen-deficient atmosphere; above 23.5% is classified as oxygen-enriched (fire and combustion risk). When the SST1-O-24 alarms, the atmosphere has crossed a specific OSHA-defined boundary. Because the setpoints are factory-set, you don't need to train workers on setpoint programming, and there's no risk of accidentally reconfiguring a monitor away from a compliant threshold in the field.
Who buys the SST1-O-24 for O2 monitoring:
- Confined-space entry teams on refinery, chemical plant, or process-vessel turnarounds where inert-atmosphere risk is real
- Food and beverage packaging operations using nitrogen — modified-atmosphere packaging, meat processing, produce cold storage
- Breweries and wineries handling fermentation CO2 in cellars and enclosed fermentation rooms
- Cryogenics operations — LOX (liquid oxygen) and LN2 (liquid nitrogen) storage and dispensing where boil-off can displace atmospheric oxygen
- Semiconductor fabs with nitrogen-purged reactors, CVD processes, and cleanroom areas
- Pharmaceutical facilities with inert-atmosphere reactors and process areas
- Medical gas facilities — O2 storage, distribution, and manifold operations
- Fire investigation crews on structure fires where post-fire O2 depletion in enclosed spaces is a real risk
- Mine rescue and industrial rescue teams needing low-cost grab-and-go O2 monitoring for atmosphere assessment during entry
- Training programs using disposable monitors for teaching confined-space entry protocols
Sensor and alarm specifications:
Sensor
Gas measuring range
Low alarm (factory-set)
High alarm (factory-set)
O2 (2-year fixed life)
0 – 25.0% by volume
19.5%
(OSHA oxygen-deficient threshold)
23.5%
(OSHA oxygen-enriched threshold)
PK Safety services the full WatchGas SST line with factory-trained technicians in-house. The SST1 Limited-Life alert-only monitors don't require calibration during their fixed lifespan (the whole point of the design), but if you're mixing them with a fleet of the serviceable SST1 line — or with any other gas detectors — PK Safety supports the full WatchGas SST platform, plus BW/Honeywell (Factory Authorized Service Center), RKI, and RAE Systems. Call us at
800.829.9580 to talk through your O2 monitoring workflow with someone who understands both product tiers of the SST1 line and can help you pick the right one for the job.
Important lifecycle notes:
-
Warranty: One year shelf life (unactivated) then two years from activation date. Your operational clock starts the moment you turn the monitor on for the first time.
-
Once activated, the monitor cannot be shut down. It continues to run for its full two-year life span, and cannot be returned or shipped once activated (an alarm during transit is possible). Unactivated monitors can be returned normally.
-
Not resellable after activation. Buy for a specific worker or crew; the monitor stays with them.
-
The display shows MM and DD — months and days remaining before the monitor expires — not the current oxygen level.
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Number: WG01-SST1-O-24 — SST1-O-24 0–25% VOL 2-year fixed life (oxygen)
Frequently Asked Questions
How does the SST1-O-24 alert-only monitor differ from the full-instrument SST1-O?
The SST1 O2 line offers two tiers, and this is the alert-only tier.
Display and configuration: the SST1-O-24 has no digital percentage display and no user-configurable alarm setpoints — it shows months and days remaining on its lifespan and alarms when oxygen crosses either factory-set threshold. The
WatchGas SST1-O serviceable O2 monitor shows continuous percentage readouts and offers configurable low/high/TWA/STEL alarms.
Sensor lifecycle: the SST1-O-24 is non-serviceable, discarded at end-of-life after two years of continuous operation, and priced at $150 — the lowest entry point in the SST1 O2 line. The full-instrument SST1-O is serviceable — the sensor cell can be replaced, extending the monitor's service life beyond the sensor's own lifespan.
Choose the SST1-O-24 for shorter-commitment jobs (single-project confined-space work, training programs, temporary rescue-team inventory). Choose the SST1-O for fleets that stay in continuous service across multiple sensor generations. Note: unlike the SST1-H and SST1-M lines, PK Safety does not currently carry a 3-year O2 variant.
What are the factory-set alarm thresholds, and how do they align with OSHA?
The SST1-O-24 ships with factory-set alarms of Low 19.5% and High 23.5%. Both are anchored to OSHA's confined-space atmosphere classifications, which are the primary regulatory reference for oxygen monitoring in U.S. industrial settings:
Below 19.5% is classified as an oxygen-deficient atmosphere under OSHA's Permit-Required Confined Spaces standard, 29 CFR 1910.146. Below this threshold, the atmosphere is not safe for entry without supplemental respiratory protection.
Above 23.5% is classified as oxygen-enriched. This is a fire and combustion risk, not a respiratory hazard — elevated O2 dramatically accelerates combustion of materials that would otherwise burn slowly or not at all.
The SST1-O-24's alarms match those OSHA classifications exactly. Because the setpoints are factory-set (not user-configurable), you don't need to train workers on setpoint programming, and there's no risk of a monitor being accidentally reconfigured away from a compliant threshold in the field.
Note that OSHA does not set a Permissible Exposure Limit (PEL) for oxygen in the way it does for toxic gases like H2S or CO — oxygen isn't a toxin. The regulatory framework for O2 monitoring is atmospheric classification, not exposure limits.
Why is oxygen depletion so dangerous — and why can't workers detect it?
Oxygen depletion is the danger that hides in plain sight. The gases that typically displace O2 in industrial settings — nitrogen, argon, helium, carbon dioxide, methane — are colorless and odorless. Workers get no sensory warning that oxygen levels are falling.
The physiology of hypoxia makes it worse. Unlike CO exposure (which triggers headache and dizziness workers can notice) or H2S exposure (which has a rotten-egg smell at low ppm), oxygen depletion impairs the very cognitive function needed to recognize the danger. At around 16% oxygen, cognitive function starts to decline. By 12%, workers typically stop recognizing they're in danger and can even feel euphoric or unconcerned. At 8% or below, unconsciousness can occur within minutes without warning.
A continuous instrument alarm is the only reliable warning. Whether you use a full-instrument SST1-O for continuous percentage readouts or an alert-only SST1-O-24 for factory-set threshold alarming, the monitor is the difference between recognizing a hazardous atmosphere in time and getting caught by it.
What does "2-year" actually mean? When does the clock start?
The lifecycle has two phases. Before activation, the monitor has a one-year shelf life (from manufacture date) during which it can sit unactivated in a warehouse or on a shelf without draining any capability. Once you press the activation button for the first time, the monitor runs continuously for two years — no user intervention required, no calibration, no battery replacement, no charging.
The display shows MM (months) and DD (days) remaining on the monitor's operational life so workers can see how much time is left. At the end of the two-year lifespan, the monitor stops functioning and gets discarded.
Does the SST1-O-24 work with the WatchGas SST-DOCK and SST-KIOSK?
Partially. The SST1-O-24 can be bump-tested using the
WatchGas SST-DOCK — useful for verifying the monitor still alarms correctly at a given point in its two-year lifespan. However, it cannot be calibrated (the factory-set thresholds are permanent by design).
The
WatchGas SST-KIOSK compliance kiosk can check in the SST1-O-24 and log its alarm-event history and remaining lifespan to fleet software — same as the full-instrument SST1 line.
How does PK Safety support the SST1-O-24 after purchase?
PK Safety carries the full WatchGas SST line, including both tiers of O2 monitoring (serviceable SST1-O and 2-year SST1-O-24). Since the SST1-O-24 doesn't require calibration or maintenance during its fixed two-year lifespan, post-sale support is primarily replacement (when a unit approaches end-of-life) and mixed-fleet coordination if you're running Limited-Life alongside full-instrument SST1 monitors or other brands.
Call
800.829.9580 to talk through your O2 monitoring workflow with someone who understands both tiers of the SST1 line — not a call-center script.
Not sure which SST1 O2 tier fits your workflow? Call PK Safety at 800.829.9580. A person who knows the serviceable / alert-only choice will pick up.
Read more
Description
Not every O2 monitor needs to give you a percentage readout. Sometimes the job just needs a badge that alarms when the atmosphere isn't breathable — no calibration schedule, no battery replacement cycle, no training curve. That's what the SST1 Limited-Life line is for.
Oxygen depletion is the danger that hides in plain sight. The gases that displace O2 in industrial settings — nitrogen, argon, helium, carbon dioxide, methane — are colorless and odorless. Workers get no sensory warning that oxygen levels are falling. And unlike CO or H2S where symptoms give some warning, O2 depletion has a nasty physiology: cognitive impairment begins around 16% oxygen, workers stop recognizing they're in danger by ~12%, and unconsciousness can occur within minutes at 8%. The monitor is the only warning because the physiology itself impairs the judgment needed to notice.
The WatchGas SST1 2-Year O2 gas detector is an alert-only monitor: no digital percentage display, factory-set alarm setpoints anchored to OSHA's confined-space atmosphere classifications, non-serviceable, and no maintenance required. Activate it once, and it runs continuously for two years — no calibration, no battery replacement, no charging — alarming immediately when oxygen falls below 19.5% (deficient) or rises above 23.5% (enriched). At $150, it's the lowest-cost O2 monitor in the SST1 line — designed for jobs that finish inside two years.
Two ways to run O2 monitoring — pick the one that fits your job.
The SST1 O2 line covers both tiers:
- Full-instrument, serviceable: the WatchGas SST1-O serviceable O2 monitor — digital percentage readout, configurable low/high/TWA/STEL alarms, replaceable sensor cell at end-of-life, integration with the WatchGas SST platform. Higher upfront cost; lowest lifecycle cost when the monitor stays in service for years.
- Limited-life, alert-only (this SKU): $150, no display, factory-set alarms at OSHA's confined-space thresholds, no maintenance for two years, discarded at end-of-life. Simpler operation; ideal for jobs where a full instrument is over-spec.
Factory-set alarm thresholds, anchored to OSHA's confined-space atmosphere classifications: Low 19.5% and High 23.5% match exactly to OSHA's regulatory definitions under 29 CFR 1910.146 — the Permit-Required Confined Spaces standard. Below 19.5% is classified as an oxygen-deficient atmosphere; above 23.5% is classified as oxygen-enriched (fire and combustion risk). When the SST1-O-24 alarms, the atmosphere has crossed a specific OSHA-defined boundary. Because the setpoints are factory-set, you don't need to train workers on setpoint programming, and there's no risk of accidentally reconfiguring a monitor away from a compliant threshold in the field.
Who buys the SST1-O-24 for O2 monitoring:
- Confined-space entry teams on refinery, chemical plant, or process-vessel turnarounds where inert-atmosphere risk is real
- Food and beverage packaging operations using nitrogen — modified-atmosphere packaging, meat processing, produce cold storage
- Breweries and wineries handling fermentation CO2 in cellars and enclosed fermentation rooms
- Cryogenics operations — LOX (liquid oxygen) and LN2 (liquid nitrogen) storage and dispensing where boil-off can displace atmospheric oxygen
- Semiconductor fabs with nitrogen-purged reactors, CVD processes, and cleanroom areas
- Pharmaceutical facilities with inert-atmosphere reactors and process areas
- Medical gas facilities — O2 storage, distribution, and manifold operations
- Fire investigation crews on structure fires where post-fire O2 depletion in enclosed spaces is a real risk
- Mine rescue and industrial rescue teams needing low-cost grab-and-go O2 monitoring for atmosphere assessment during entry
- Training programs using disposable monitors for teaching confined-space entry protocols
Sensor and alarm specifications:
| Sensor | Gas measuring range | Low alarm (factory-set) | High alarm (factory-set) |
| O2 (2-year fixed life) | 0 – 25.0% by volume | 19.5% (OSHA oxygen-deficient threshold) | 23.5% (OSHA oxygen-enriched threshold) |
PK Safety services the full WatchGas SST line with factory-trained technicians in-house. The SST1 Limited-Life alert-only monitors don't require calibration during their fixed lifespan (the whole point of the design), but if you're mixing them with a fleet of the serviceable SST1 line — or with any other gas detectors — PK Safety supports the full WatchGas SST platform, plus BW/Honeywell (Factory Authorized Service Center), RKI, and RAE Systems. Call us at 800.829.9580 to talk through your O2 monitoring workflow with someone who understands both product tiers of the SST1 line and can help you pick the right one for the job.
Important lifecycle notes:
- Warranty: One year shelf life (unactivated) then two years from activation date. Your operational clock starts the moment you turn the monitor on for the first time.
- Once activated, the monitor cannot be shut down. It continues to run for its full two-year life span, and cannot be returned or shipped once activated (an alarm during transit is possible). Unactivated monitors can be returned normally.
- Not resellable after activation. Buy for a specific worker or crew; the monitor stays with them.
- The display shows MM and DD — months and days remaining before the monitor expires — not the current oxygen level.
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Number: WG01-SST1-O-24 — SST1-O-24 0–25% VOL 2-year fixed life (oxygen)
Frequently Asked Questions
How does the SST1-O-24 alert-only monitor differ from the full-instrument SST1-O?
The SST1 O2 line offers two tiers, and this is the alert-only tier.
Display and configuration: the SST1-O-24 has no digital percentage display and no user-configurable alarm setpoints — it shows months and days remaining on its lifespan and alarms when oxygen crosses either factory-set threshold. The WatchGas SST1-O serviceable O2 monitor shows continuous percentage readouts and offers configurable low/high/TWA/STEL alarms.
Sensor lifecycle: the SST1-O-24 is non-serviceable, discarded at end-of-life after two years of continuous operation, and priced at $150 — the lowest entry point in the SST1 O2 line. The full-instrument SST1-O is serviceable — the sensor cell can be replaced, extending the monitor's service life beyond the sensor's own lifespan.
Choose the SST1-O-24 for shorter-commitment jobs (single-project confined-space work, training programs, temporary rescue-team inventory). Choose the SST1-O for fleets that stay in continuous service across multiple sensor generations. Note: unlike the SST1-H and SST1-M lines, PK Safety does not currently carry a 3-year O2 variant.
What are the factory-set alarm thresholds, and how do they align with OSHA?
The SST1-O-24 ships with factory-set alarms of Low 19.5% and High 23.5%. Both are anchored to OSHA's confined-space atmosphere classifications, which are the primary regulatory reference for oxygen monitoring in U.S. industrial settings:
Below 19.5% is classified as an oxygen-deficient atmosphere under OSHA's Permit-Required Confined Spaces standard, 29 CFR 1910.146. Below this threshold, the atmosphere is not safe for entry without supplemental respiratory protection.
Above 23.5% is classified as oxygen-enriched. This is a fire and combustion risk, not a respiratory hazard — elevated O2 dramatically accelerates combustion of materials that would otherwise burn slowly or not at all.
The SST1-O-24's alarms match those OSHA classifications exactly. Because the setpoints are factory-set (not user-configurable), you don't need to train workers on setpoint programming, and there's no risk of a monitor being accidentally reconfigured away from a compliant threshold in the field.
Note that OSHA does not set a Permissible Exposure Limit (PEL) for oxygen in the way it does for toxic gases like H2S or CO — oxygen isn't a toxin. The regulatory framework for O2 monitoring is atmospheric classification, not exposure limits.
Why is oxygen depletion so dangerous — and why can't workers detect it?
Oxygen depletion is the danger that hides in plain sight. The gases that typically displace O2 in industrial settings — nitrogen, argon, helium, carbon dioxide, methane — are colorless and odorless. Workers get no sensory warning that oxygen levels are falling.
The physiology of hypoxia makes it worse. Unlike CO exposure (which triggers headache and dizziness workers can notice) or H2S exposure (which has a rotten-egg smell at low ppm), oxygen depletion impairs the very cognitive function needed to recognize the danger. At around 16% oxygen, cognitive function starts to decline. By 12%, workers typically stop recognizing they're in danger and can even feel euphoric or unconcerned. At 8% or below, unconsciousness can occur within minutes without warning.
A continuous instrument alarm is the only reliable warning. Whether you use a full-instrument SST1-O for continuous percentage readouts or an alert-only SST1-O-24 for factory-set threshold alarming, the monitor is the difference between recognizing a hazardous atmosphere in time and getting caught by it.
What does "2-year" actually mean? When does the clock start?
The lifecycle has two phases. Before activation, the monitor has a one-year shelf life (from manufacture date) during which it can sit unactivated in a warehouse or on a shelf without draining any capability. Once you press the activation button for the first time, the monitor runs continuously for two years — no user intervention required, no calibration, no battery replacement, no charging.
The display shows MM (months) and DD (days) remaining on the monitor's operational life so workers can see how much time is left. At the end of the two-year lifespan, the monitor stops functioning and gets discarded.
Does the SST1-O-24 work with the WatchGas SST-DOCK and SST-KIOSK?
Partially. The SST1-O-24 can be bump-tested using the WatchGas SST-DOCK — useful for verifying the monitor still alarms correctly at a given point in its two-year lifespan. However, it cannot be calibrated (the factory-set thresholds are permanent by design).
The WatchGas SST-KIOSK compliance kiosk can check in the SST1-O-24 and log its alarm-event history and remaining lifespan to fleet software — same as the full-instrument SST1 line.
How does PK Safety support the SST1-O-24 after purchase?
PK Safety carries the full WatchGas SST line, including both tiers of O2 monitoring (serviceable SST1-O and 2-year SST1-O-24). Since the SST1-O-24 doesn't require calibration or maintenance during its fixed two-year lifespan, post-sale support is primarily replacement (when a unit approaches end-of-life) and mixed-fleet coordination if you're running Limited-Life alongside full-instrument SST1 monitors or other brands.
Call 800.829.9580 to talk through your O2 monitoring workflow with someone who understands both tiers of the SST1 line — not a call-center script.
Not sure which SST1 O2 tier fits your workflow? Call PK Safety at 800.829.9580. A person who knows the serviceable / alert-only choice will pick up.
Not every O2 monitor needs to give you a percentage readout. Sometimes the job just needs a badge that alarms when the atmosphere isn't breathable — no calibration schedule, no battery replacement cycle, no training curve. That's what the SST1 Limited-Life line is for.
Oxygen depletion is the danger that hides in plain sight. The gases that displace O2 in industrial settings — nitrogen, argon, helium, carbon dioxide, methane — are colorless and odorless. Workers get no sensory warning that oxygen levels are falling. And unlike CO or H2S where symptoms give some warning, O2 depletion has a nasty physiology: cognitive impairment begins around 16% oxygen, workers stop recognizing they're in danger by ~12%, and unconsciousness can occur within minutes at 8%. The monitor is the only warning because the physiology itself impairs the judgment needed to notice.
The WatchGas SST1 2-Year O2 gas detector is an alert-only monitor: no digital percentage display, factory-set alarm setpoints anchored to OSHA's confined-space atmosphere classifications, non-serviceable, and no maintenance required. Activate it once, and it runs continuously for two years — no calibration, no battery replacement, no charging — alarming immediately when oxygen falls below 19.5% (deficient) or rises above 23.5% (enriched). At $150, it's the lowest-cost O2 monitor in the SST1 line — designed for jobs that finish inside two years.
Two ways to run O2 monitoring — pick the one that fits your job.
The SST1 O2 line covers both tiers:
- Full-instrument, serviceable: the WatchGas SST1-O serviceable O2 monitor — digital percentage readout, configurable low/high/TWA/STEL alarms, replaceable sensor cell at end-of-life, integration with the WatchGas SST platform. Higher upfront cost; lowest lifecycle cost when the monitor stays in service for years.
- Limited-life, alert-only (this SKU): $150, no display, factory-set alarms at OSHA's confined-space thresholds, no maintenance for two years, discarded at end-of-life. Simpler operation; ideal for jobs where a full instrument is over-spec.
Factory-set alarm thresholds, anchored to OSHA's confined-space atmosphere classifications: Low 19.5% and High 23.5% match exactly to OSHA's regulatory definitions under 29 CFR 1910.146 — the Permit-Required Confined Spaces standard. Below 19.5% is classified as an oxygen-deficient atmosphere; above 23.5% is classified as oxygen-enriched (fire and combustion risk). When the SST1-O-24 alarms, the atmosphere has crossed a specific OSHA-defined boundary. Because the setpoints are factory-set, you don't need to train workers on setpoint programming, and there's no risk of accidentally reconfiguring a monitor away from a compliant threshold in the field.
Who buys the SST1-O-24 for O2 monitoring:
- Confined-space entry teams on refinery, chemical plant, or process-vessel turnarounds where inert-atmosphere risk is real
- Food and beverage packaging operations using nitrogen — modified-atmosphere packaging, meat processing, produce cold storage
- Breweries and wineries handling fermentation CO2 in cellars and enclosed fermentation rooms
- Cryogenics operations — LOX (liquid oxygen) and LN2 (liquid nitrogen) storage and dispensing where boil-off can displace atmospheric oxygen
- Semiconductor fabs with nitrogen-purged reactors, CVD processes, and cleanroom areas
- Pharmaceutical facilities with inert-atmosphere reactors and process areas
- Medical gas facilities — O2 storage, distribution, and manifold operations
- Fire investigation crews on structure fires where post-fire O2 depletion in enclosed spaces is a real risk
- Mine rescue and industrial rescue teams needing low-cost grab-and-go O2 monitoring for atmosphere assessment during entry
- Training programs using disposable monitors for teaching confined-space entry protocols
Sensor and alarm specifications:
| Sensor | Gas measuring range | Low alarm (factory-set) | High alarm (factory-set) |
| O2 (2-year fixed life) | 0 – 25.0% by volume | 19.5% (OSHA oxygen-deficient threshold) | 23.5% (OSHA oxygen-enriched threshold) |
PK Safety services the full WatchGas SST line with factory-trained technicians in-house. The SST1 Limited-Life alert-only monitors don't require calibration during their fixed lifespan (the whole point of the design), but if you're mixing them with a fleet of the serviceable SST1 line — or with any other gas detectors — PK Safety supports the full WatchGas SST platform, plus BW/Honeywell (Factory Authorized Service Center), RKI, and RAE Systems. Call us at 800.829.9580 to talk through your O2 monitoring workflow with someone who understands both product tiers of the SST1 line and can help you pick the right one for the job.
Important lifecycle notes:
- Warranty: One year shelf life (unactivated) then two years from activation date. Your operational clock starts the moment you turn the monitor on for the first time.
- Once activated, the monitor cannot be shut down. It continues to run for its full two-year life span, and cannot be returned or shipped once activated (an alarm during transit is possible). Unactivated monitors can be returned normally.
- Not resellable after activation. Buy for a specific worker or crew; the monitor stays with them.
- The display shows MM and DD — months and days remaining before the monitor expires — not the current oxygen level.
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Number: WG01-SST1-O-24 — SST1-O-24 0–25% VOL 2-year fixed life (oxygen)
Frequently Asked Questions
How does the SST1-O-24 alert-only monitor differ from the full-instrument SST1-O?
The SST1 O2 line offers two tiers, and this is the alert-only tier.
Display and configuration: the SST1-O-24 has no digital percentage display and no user-configurable alarm setpoints — it shows months and days remaining on its lifespan and alarms when oxygen crosses either factory-set threshold. The WatchGas SST1-O serviceable O2 monitor shows continuous percentage readouts and offers configurable low/high/TWA/STEL alarms.
Sensor lifecycle: the SST1-O-24 is non-serviceable, discarded at end-of-life after two years of continuous operation, and priced at $150 — the lowest entry point in the SST1 O2 line. The full-instrument SST1-O is serviceable — the sensor cell can be replaced, extending the monitor's service life beyond the sensor's own lifespan.
Choose the SST1-O-24 for shorter-commitment jobs (single-project confined-space work, training programs, temporary rescue-team inventory). Choose the SST1-O for fleets that stay in continuous service across multiple sensor generations. Note: unlike the SST1-H and SST1-M lines, PK Safety does not currently carry a 3-year O2 variant.
What are the factory-set alarm thresholds, and how do they align with OSHA?
The SST1-O-24 ships with factory-set alarms of Low 19.5% and High 23.5%. Both are anchored to OSHA's confined-space atmosphere classifications, which are the primary regulatory reference for oxygen monitoring in U.S. industrial settings:
Below 19.5% is classified as an oxygen-deficient atmosphere under OSHA's Permit-Required Confined Spaces standard, 29 CFR 1910.146. Below this threshold, the atmosphere is not safe for entry without supplemental respiratory protection.
Above 23.5% is classified as oxygen-enriched. This is a fire and combustion risk, not a respiratory hazard — elevated O2 dramatically accelerates combustion of materials that would otherwise burn slowly or not at all.
The SST1-O-24's alarms match those OSHA classifications exactly. Because the setpoints are factory-set (not user-configurable), you don't need to train workers on setpoint programming, and there's no risk of a monitor being accidentally reconfigured away from a compliant threshold in the field.
Note that OSHA does not set a Permissible Exposure Limit (PEL) for oxygen in the way it does for toxic gases like H2S or CO — oxygen isn't a toxin. The regulatory framework for O2 monitoring is atmospheric classification, not exposure limits.
Why is oxygen depletion so dangerous — and why can't workers detect it?
Oxygen depletion is the danger that hides in plain sight. The gases that typically displace O2 in industrial settings — nitrogen, argon, helium, carbon dioxide, methane — are colorless and odorless. Workers get no sensory warning that oxygen levels are falling.
The physiology of hypoxia makes it worse. Unlike CO exposure (which triggers headache and dizziness workers can notice) or H2S exposure (which has a rotten-egg smell at low ppm), oxygen depletion impairs the very cognitive function needed to recognize the danger. At around 16% oxygen, cognitive function starts to decline. By 12%, workers typically stop recognizing they're in danger and can even feel euphoric or unconcerned. At 8% or below, unconsciousness can occur within minutes without warning.
A continuous instrument alarm is the only reliable warning. Whether you use a full-instrument SST1-O for continuous percentage readouts or an alert-only SST1-O-24 for factory-set threshold alarming, the monitor is the difference between recognizing a hazardous atmosphere in time and getting caught by it.
What does "2-year" actually mean? When does the clock start?
The lifecycle has two phases. Before activation, the monitor has a one-year shelf life (from manufacture date) during which it can sit unactivated in a warehouse or on a shelf without draining any capability. Once you press the activation button for the first time, the monitor runs continuously for two years — no user intervention required, no calibration, no battery replacement, no charging.
The display shows MM (months) and DD (days) remaining on the monitor's operational life so workers can see how much time is left. At the end of the two-year lifespan, the monitor stops functioning and gets discarded.
Does the SST1-O-24 work with the WatchGas SST-DOCK and SST-KIOSK?
Partially. The SST1-O-24 can be bump-tested using the WatchGas SST-DOCK — useful for verifying the monitor still alarms correctly at a given point in its two-year lifespan. However, it cannot be calibrated (the factory-set thresholds are permanent by design).
The WatchGas SST-KIOSK compliance kiosk can check in the SST1-O-24 and log its alarm-event history and remaining lifespan to fleet software — same as the full-instrument SST1 line.
How does PK Safety support the SST1-O-24 after purchase?
PK Safety carries the full WatchGas SST line, including both tiers of O2 monitoring (serviceable SST1-O and 2-year SST1-O-24). Since the SST1-O-24 doesn't require calibration or maintenance during its fixed two-year lifespan, post-sale support is primarily replacement (when a unit approaches end-of-life) and mixed-fleet coordination if you're running Limited-Life alongside full-instrument SST1 monitors or other brands.
Call 800.829.9580 to talk through your O2 monitoring workflow with someone who understands both tiers of the SST1 line — not a call-center script.
Not sure which SST1 O2 tier fits your workflow? Call PK Safety at 800.829.9580. A person who knows the serviceable / alert-only choice will pick up.
Specifications
Specifications
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MPN
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Gas Type
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Product Weight (lbs.)
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Height (in.)
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Length (in.)
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Width (in.)
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Country of Origin
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Keep your team protected & compliant!
- Expert guidance tailored to your specific needs
- Access responsive customer support when you need it
- Enjoy fast shipping directly to your location
- Benefit from extensive industry knowledge—75+ years of experience
- In-house gas detection calibration & repair services available
