WatchGas SST1 2 Year CO Gas Detector SST1-M-24
Description
Not every CO monitor needs to give you a number. Sometimes the job just needs a badge that alarms when you're in danger — no calibration schedule, no battery replacement cycle, no training curve. That's what the SST1 Limited-Life line is for.
Carbon monoxide is odorless, colorless, and tasteless. Workers get zero sensory warning that CO is accumulating in an enclosed space — not until the physiological effects kick in (headache, dizziness, confusion), and by then the exposure is already past regulatory limits and can escalate quickly. For CO, the monitor isn't a backup to your senses. It IS the warning system.
The WatchGas SST1 2-Year CO gas detector is an alert-only monitor: no digital ppm display, factory-set alarm setpoints anchored to the NIOSH REL for carbon monoxide, 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 CO exceeds the factory-set thresholds. At $150, it's the shortest-commitment, lowest-cost CO monitor in the SST1 line — designed for jobs that finish inside two years.
Three ways to run CO monitoring — pick the one that fits your job.
The SST1 line covers all three tiers:
-
Full-instrument, serviceable: the
WatchGas SST1-M serviceable CO monitor — digital ppm readout, configurable low/high/TWA/STEL alarms, replaceable sensor cell at end-of-life. Higher upfront cost; lowest lifecycle cost for fleets in continuous multi-year service.
-
Alert-only, 3-year lifespan: the
WatchGas SST1-M-36 3-Year Alert-Only ($210) — no display, factory-set alarms, non-serviceable, three-year operational life.
-
Alert-only, 2-year lifespan (this SKU): $150, same alert-only design, two-year operational life. Lowest upfront cost; ideal for shorter-duration commitments like single-project contractor work, seasonal operations, grab-and-go emergency inventory, or training programs.
Factory-set alarm thresholds, anchored to U.S. regulatory exposure limits for carbon monoxide: Low 35 ppm matches the NIOSH REL TWA (35 ppm 8-hour). High 200 ppm matches the NIOSH REL Ceiling (200 ppm not to be exceeded at any moment). Both are stricter than OSHA's PEL of 50 ppm 8-hour TWA under 29 CFR 1910.1000 Table Z-1, which does not establish a separate ceiling for CO in general industry. Because the alarms are factory-set (not user-configurable), 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-M-24 for CO monitoring:
- Contractors and subcontractors on short-duration CO-exposed work — boiler service, HVAC installation, industrial turnarounds
- Small boiler-operator crews at facilities without full safety-program overhead
- Municipal fire departments and mutual-aid teams needing low-cost grab-and-go CO inventory for post-fire investigation and structural fire response
- HVAC and plumbing technicians on temporary or per-project deployments
- Grain drying and crop processing operators on seasonal cycles — the 2-year lifespan matches multi-season contract periods
- Vehicle emissions monitoring at garages, warehouses with propane forklifts, tunnels, or parking structures where the monitoring need is temporary
- Training programs using disposable monitors for teaching — shorter lifespan means faster inventory turn at lowest unit cost
- Consultants and auditors on temporary deployments at client sites
Sensor and alarm specifications:
Sensor
Gas measuring range
Low alarm (factory-set)
High alarm (factory-set)
CO (2-year fixed life)
0 – 2000 ppm
35 ppm
(NIOSH REL TWA)
200 ppm
(NIOSH REL Ceiling)
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 CO monitoring workflow with someone who understands all three tiers of the SST1 CO 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 gas concentration.
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Number: WG01-SST1-M-24 — SST1-M-24 CO 0–2000 ppm 2-year fixed life (carbon monoxide)
Frequently Asked Questions
How does the SST1-M-24 alert-only monitor differ from the full-instrument SST1-M and the 3-year SST1-M-36?
The SST1 platform offers three tiers for CO monitoring, and this is the entry-price alert-only tier.
Display and configuration: the SST1-M-24 has no digital ppm display and no user-configurable alarm setpoints — it shows months and days remaining on its lifespan and alarms when CO exceeds its factory-set threshold. The
WatchGas SST1-M serviceable CO monitor shows continuous ppm readouts and offers configurable low/high/TWA/STEL alarms.
Sensor lifecycle and price: the SST1-M-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 CO line. The
SST1-M-36 3-Year Alert-Only is the same design but with a three-year lifespan and higher price ($210). The full-instrument SST1-M is serviceable — the sensor cell can be replaced, extending the monitor's service life beyond the sensor's own lifespan.
Choose the SST1-M-24 for the shortest-commitment jobs (single-project contractor work, seasonal operations, grab-and-go emergency inventory, training). Choose the SST1-M-36 for jobs that will run through the full three-year sensor life. Choose the SST1-M for fleets that stay in continuous service across multiple sensor generations.
What are the factory-set alarm thresholds, and how do they align with OSHA and NIOSH?
The SST1-M-24 ships with factory-set alarms of Low 35 ppm and High 200 ppm. Both are anchored to the NIOSH Recommended Exposure Limit for carbon monoxide, which is stricter than the OSHA PEL for CO:
OSHA's PEL for carbon monoxide under 29 CFR 1910.1000 Table Z-1 is 50 ppm as an 8-hour time-weighted average. OSHA does not set a separate ceiling limit for CO in general industry.
NIOSH's REL is stricter: 35 ppm 8-hour TWA plus a 200 ppm ceiling not to be exceeded at any moment.
The SST1-M-24's
Low 35 ppm alarm matches the NIOSH REL TWA exactly, and the
High 200 ppm alarm matches the NIOSH REL Ceiling 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.
If your facility's internal exposure program requires stricter setpoints than NIOSH — for example, ACGIH's TLV-TWA of 25 ppm for CO — the full-instrument
WatchGas SST1-M serviceable CO monitor is the right choice; its low/high/TWA/STEL alarms are all configurable.
Why is CO monitoring different from monitoring other gases?
Carbon monoxide is odorless, colorless, and tasteless. Unlike H2S (rotten-egg smell at low ppm), ammonia (pungent), or sulfur dioxide (sharp acid smell), CO gives workers zero sensory warning that concentrations are building up in an enclosed space. Symptoms of CO exposure — headache, dizziness, confusion, nausea — typically don't kick in until concentrations are already past regulatory limits, and CO poisoning can escalate quickly from mild symptoms to loss of consciousness.
That physiology has one operational implication for CO monitoring: the monitor isn't a backup or a confirmation of what workers can already sense. It IS the warning system. Whether you use a full-instrument SST1-M for continuous ppm readouts or an alert-only SST1-M-24 for factory-set threshold alarming, the monitor is the difference between recognizing a CO buildup 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-M-24 work with the WatchGas SST-DOCK and SST-KIOSK?
Partially. The SST1-M-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-M-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-M-24 after purchase?
PK Safety carries the full WatchGas SST line, including all three tiers of CO monitoring (serviceable SST1-M, 3-year SST1-M-36, 2-year SST1-M-24). Since the SST1-M-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 CO monitoring workflow with someone who understands all three tiers of the SST1 line — not a call-center script.
Not sure which SST1 CO tier fits your workflow? Call PK Safety at 800.829.9580. A person who knows the serviceable / 3-year alert-only / 2-year alert-only choice will pick up.
Read more
Description
Not every CO monitor needs to give you a number. Sometimes the job just needs a badge that alarms when you're in danger — no calibration schedule, no battery replacement cycle, no training curve. That's what the SST1 Limited-Life line is for.
Carbon monoxide is odorless, colorless, and tasteless. Workers get zero sensory warning that CO is accumulating in an enclosed space — not until the physiological effects kick in (headache, dizziness, confusion), and by then the exposure is already past regulatory limits and can escalate quickly. For CO, the monitor isn't a backup to your senses. It IS the warning system.
The WatchGas SST1 2-Year CO gas detector is an alert-only monitor: no digital ppm display, factory-set alarm setpoints anchored to the NIOSH REL for carbon monoxide, 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 CO exceeds the factory-set thresholds. At $150, it's the shortest-commitment, lowest-cost CO monitor in the SST1 line — designed for jobs that finish inside two years.
Three ways to run CO monitoring — pick the one that fits your job.
The SST1 line covers all three tiers:
- Full-instrument, serviceable: the WatchGas SST1-M serviceable CO monitor — digital ppm readout, configurable low/high/TWA/STEL alarms, replaceable sensor cell at end-of-life. Higher upfront cost; lowest lifecycle cost for fleets in continuous multi-year service.
- Alert-only, 3-year lifespan: the WatchGas SST1-M-36 3-Year Alert-Only ($210) — no display, factory-set alarms, non-serviceable, three-year operational life.
- Alert-only, 2-year lifespan (this SKU): $150, same alert-only design, two-year operational life. Lowest upfront cost; ideal for shorter-duration commitments like single-project contractor work, seasonal operations, grab-and-go emergency inventory, or training programs.
Factory-set alarm thresholds, anchored to U.S. regulatory exposure limits for carbon monoxide: Low 35 ppm matches the NIOSH REL TWA (35 ppm 8-hour). High 200 ppm matches the NIOSH REL Ceiling (200 ppm not to be exceeded at any moment). Both are stricter than OSHA's PEL of 50 ppm 8-hour TWA under 29 CFR 1910.1000 Table Z-1, which does not establish a separate ceiling for CO in general industry. Because the alarms are factory-set (not user-configurable), 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-M-24 for CO monitoring:
- Contractors and subcontractors on short-duration CO-exposed work — boiler service, HVAC installation, industrial turnarounds
- Small boiler-operator crews at facilities without full safety-program overhead
- Municipal fire departments and mutual-aid teams needing low-cost grab-and-go CO inventory for post-fire investigation and structural fire response
- HVAC and plumbing technicians on temporary or per-project deployments
- Grain drying and crop processing operators on seasonal cycles — the 2-year lifespan matches multi-season contract periods
- Vehicle emissions monitoring at garages, warehouses with propane forklifts, tunnels, or parking structures where the monitoring need is temporary
- Training programs using disposable monitors for teaching — shorter lifespan means faster inventory turn at lowest unit cost
- Consultants and auditors on temporary deployments at client sites
Sensor and alarm specifications:
| Sensor | Gas measuring range | Low alarm (factory-set) | High alarm (factory-set) |
| CO (2-year fixed life) | 0 – 2000 ppm | 35 ppm (NIOSH REL TWA) | 200 ppm (NIOSH REL Ceiling) |
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 CO monitoring workflow with someone who understands all three tiers of the SST1 CO 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 gas concentration.
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Number: WG01-SST1-M-24 — SST1-M-24 CO 0–2000 ppm 2-year fixed life (carbon monoxide)
Frequently Asked Questions
How does the SST1-M-24 alert-only monitor differ from the full-instrument SST1-M and the 3-year SST1-M-36?
The SST1 platform offers three tiers for CO monitoring, and this is the entry-price alert-only tier.
Display and configuration: the SST1-M-24 has no digital ppm display and no user-configurable alarm setpoints — it shows months and days remaining on its lifespan and alarms when CO exceeds its factory-set threshold. The WatchGas SST1-M serviceable CO monitor shows continuous ppm readouts and offers configurable low/high/TWA/STEL alarms.
Sensor lifecycle and price: the SST1-M-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 CO line. The SST1-M-36 3-Year Alert-Only is the same design but with a three-year lifespan and higher price ($210). The full-instrument SST1-M is serviceable — the sensor cell can be replaced, extending the monitor's service life beyond the sensor's own lifespan.
Choose the SST1-M-24 for the shortest-commitment jobs (single-project contractor work, seasonal operations, grab-and-go emergency inventory, training). Choose the SST1-M-36 for jobs that will run through the full three-year sensor life. Choose the SST1-M for fleets that stay in continuous service across multiple sensor generations.
What are the factory-set alarm thresholds, and how do they align with OSHA and NIOSH?
The SST1-M-24 ships with factory-set alarms of Low 35 ppm and High 200 ppm. Both are anchored to the NIOSH Recommended Exposure Limit for carbon monoxide, which is stricter than the OSHA PEL for CO:
OSHA's PEL for carbon monoxide under 29 CFR 1910.1000 Table Z-1 is 50 ppm as an 8-hour time-weighted average. OSHA does not set a separate ceiling limit for CO in general industry.
NIOSH's REL is stricter: 35 ppm 8-hour TWA plus a 200 ppm ceiling not to be exceeded at any moment.
The SST1-M-24's Low 35 ppm alarm matches the NIOSH REL TWA exactly, and the High 200 ppm alarm matches the NIOSH REL Ceiling 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.
If your facility's internal exposure program requires stricter setpoints than NIOSH — for example, ACGIH's TLV-TWA of 25 ppm for CO — the full-instrument WatchGas SST1-M serviceable CO monitor is the right choice; its low/high/TWA/STEL alarms are all configurable.
Why is CO monitoring different from monitoring other gases?
Carbon monoxide is odorless, colorless, and tasteless. Unlike H2S (rotten-egg smell at low ppm), ammonia (pungent), or sulfur dioxide (sharp acid smell), CO gives workers zero sensory warning that concentrations are building up in an enclosed space. Symptoms of CO exposure — headache, dizziness, confusion, nausea — typically don't kick in until concentrations are already past regulatory limits, and CO poisoning can escalate quickly from mild symptoms to loss of consciousness.
That physiology has one operational implication for CO monitoring: the monitor isn't a backup or a confirmation of what workers can already sense. It IS the warning system. Whether you use a full-instrument SST1-M for continuous ppm readouts or an alert-only SST1-M-24 for factory-set threshold alarming, the monitor is the difference between recognizing a CO buildup 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-M-24 work with the WatchGas SST-DOCK and SST-KIOSK?
Partially. The SST1-M-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-M-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-M-24 after purchase?
PK Safety carries the full WatchGas SST line, including all three tiers of CO monitoring (serviceable SST1-M, 3-year SST1-M-36, 2-year SST1-M-24). Since the SST1-M-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 CO monitoring workflow with someone who understands all three tiers of the SST1 line — not a call-center script.
Not sure which SST1 CO tier fits your workflow? Call PK Safety at 800.829.9580. A person who knows the serviceable / 3-year alert-only / 2-year alert-only choice will pick up.
Not every CO monitor needs to give you a number. Sometimes the job just needs a badge that alarms when you're in danger — no calibration schedule, no battery replacement cycle, no training curve. That's what the SST1 Limited-Life line is for.
Carbon monoxide is odorless, colorless, and tasteless. Workers get zero sensory warning that CO is accumulating in an enclosed space — not until the physiological effects kick in (headache, dizziness, confusion), and by then the exposure is already past regulatory limits and can escalate quickly. For CO, the monitor isn't a backup to your senses. It IS the warning system.
The WatchGas SST1 2-Year CO gas detector is an alert-only monitor: no digital ppm display, factory-set alarm setpoints anchored to the NIOSH REL for carbon monoxide, 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 CO exceeds the factory-set thresholds. At $150, it's the shortest-commitment, lowest-cost CO monitor in the SST1 line — designed for jobs that finish inside two years.
Three ways to run CO monitoring — pick the one that fits your job.
The SST1 line covers all three tiers:
- Full-instrument, serviceable: the WatchGas SST1-M serviceable CO monitor — digital ppm readout, configurable low/high/TWA/STEL alarms, replaceable sensor cell at end-of-life. Higher upfront cost; lowest lifecycle cost for fleets in continuous multi-year service.
- Alert-only, 3-year lifespan: the WatchGas SST1-M-36 3-Year Alert-Only ($210) — no display, factory-set alarms, non-serviceable, three-year operational life.
- Alert-only, 2-year lifespan (this SKU): $150, same alert-only design, two-year operational life. Lowest upfront cost; ideal for shorter-duration commitments like single-project contractor work, seasonal operations, grab-and-go emergency inventory, or training programs.
Factory-set alarm thresholds, anchored to U.S. regulatory exposure limits for carbon monoxide: Low 35 ppm matches the NIOSH REL TWA (35 ppm 8-hour). High 200 ppm matches the NIOSH REL Ceiling (200 ppm not to be exceeded at any moment). Both are stricter than OSHA's PEL of 50 ppm 8-hour TWA under 29 CFR 1910.1000 Table Z-1, which does not establish a separate ceiling for CO in general industry. Because the alarms are factory-set (not user-configurable), 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-M-24 for CO monitoring:
- Contractors and subcontractors on short-duration CO-exposed work — boiler service, HVAC installation, industrial turnarounds
- Small boiler-operator crews at facilities without full safety-program overhead
- Municipal fire departments and mutual-aid teams needing low-cost grab-and-go CO inventory for post-fire investigation and structural fire response
- HVAC and plumbing technicians on temporary or per-project deployments
- Grain drying and crop processing operators on seasonal cycles — the 2-year lifespan matches multi-season contract periods
- Vehicle emissions monitoring at garages, warehouses with propane forklifts, tunnels, or parking structures where the monitoring need is temporary
- Training programs using disposable monitors for teaching — shorter lifespan means faster inventory turn at lowest unit cost
- Consultants and auditors on temporary deployments at client sites
Sensor and alarm specifications:
| Sensor | Gas measuring range | Low alarm (factory-set) | High alarm (factory-set) |
| CO (2-year fixed life) | 0 – 2000 ppm | 35 ppm (NIOSH REL TWA) | 200 ppm (NIOSH REL Ceiling) |
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 CO monitoring workflow with someone who understands all three tiers of the SST1 CO 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 gas concentration.
Technical documents:
Brochure
Specification Sheet
Quick Start Guide
Manual
Part Number: WG01-SST1-M-24 — SST1-M-24 CO 0–2000 ppm 2-year fixed life (carbon monoxide)
Frequently Asked Questions
How does the SST1-M-24 alert-only monitor differ from the full-instrument SST1-M and the 3-year SST1-M-36?
The SST1 platform offers three tiers for CO monitoring, and this is the entry-price alert-only tier.
Display and configuration: the SST1-M-24 has no digital ppm display and no user-configurable alarm setpoints — it shows months and days remaining on its lifespan and alarms when CO exceeds its factory-set threshold. The WatchGas SST1-M serviceable CO monitor shows continuous ppm readouts and offers configurable low/high/TWA/STEL alarms.
Sensor lifecycle and price: the SST1-M-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 CO line. The SST1-M-36 3-Year Alert-Only is the same design but with a three-year lifespan and higher price ($210). The full-instrument SST1-M is serviceable — the sensor cell can be replaced, extending the monitor's service life beyond the sensor's own lifespan.
Choose the SST1-M-24 for the shortest-commitment jobs (single-project contractor work, seasonal operations, grab-and-go emergency inventory, training). Choose the SST1-M-36 for jobs that will run through the full three-year sensor life. Choose the SST1-M for fleets that stay in continuous service across multiple sensor generations.
What are the factory-set alarm thresholds, and how do they align with OSHA and NIOSH?
The SST1-M-24 ships with factory-set alarms of Low 35 ppm and High 200 ppm. Both are anchored to the NIOSH Recommended Exposure Limit for carbon monoxide, which is stricter than the OSHA PEL for CO:
OSHA's PEL for carbon monoxide under 29 CFR 1910.1000 Table Z-1 is 50 ppm as an 8-hour time-weighted average. OSHA does not set a separate ceiling limit for CO in general industry.
NIOSH's REL is stricter: 35 ppm 8-hour TWA plus a 200 ppm ceiling not to be exceeded at any moment.
The SST1-M-24's Low 35 ppm alarm matches the NIOSH REL TWA exactly, and the High 200 ppm alarm matches the NIOSH REL Ceiling 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.
If your facility's internal exposure program requires stricter setpoints than NIOSH — for example, ACGIH's TLV-TWA of 25 ppm for CO — the full-instrument WatchGas SST1-M serviceable CO monitor is the right choice; its low/high/TWA/STEL alarms are all configurable.
Why is CO monitoring different from monitoring other gases?
Carbon monoxide is odorless, colorless, and tasteless. Unlike H2S (rotten-egg smell at low ppm), ammonia (pungent), or sulfur dioxide (sharp acid smell), CO gives workers zero sensory warning that concentrations are building up in an enclosed space. Symptoms of CO exposure — headache, dizziness, confusion, nausea — typically don't kick in until concentrations are already past regulatory limits, and CO poisoning can escalate quickly from mild symptoms to loss of consciousness.
That physiology has one operational implication for CO monitoring: the monitor isn't a backup or a confirmation of what workers can already sense. It IS the warning system. Whether you use a full-instrument SST1-M for continuous ppm readouts or an alert-only SST1-M-24 for factory-set threshold alarming, the monitor is the difference between recognizing a CO buildup 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-M-24 work with the WatchGas SST-DOCK and SST-KIOSK?
Partially. The SST1-M-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-M-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-M-24 after purchase?
PK Safety carries the full WatchGas SST line, including all three tiers of CO monitoring (serviceable SST1-M, 3-year SST1-M-36, 2-year SST1-M-24). Since the SST1-M-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 CO monitoring workflow with someone who understands all three tiers of the SST1 line — not a call-center script.
Not sure which SST1 CO tier fits your workflow? Call PK Safety at 800.829.9580. A person who knows the serviceable / 3-year alert-only / 2-year alert-only choice will pick up.
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Specifications
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- 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
