Allegro Industries 9220‐01 SAR System: The Science of Supplied Air for Safer Work Environments

We often take breathing for granted. Inhale, exhale. Simple, right? But step into many workplaces – a painter’s workshop filled with solvent fumes, a renovation site clouded with fine dust, or even certain manufacturing areas – and the air transforms from life-sustaining to potentially hazardous. These invisible threats, the dusts, mists, vapors, and gases generated by work processes, can pose serious risks to our respiratory health over time.

Simple dust masks might catch larger particles, but they offer little defense against fine particulates, chemical vapors, or oxygen deficiency. When the risks escalate, we need to move beyond basic filtration and consider more robust solutions. This is where Supplied Air Respirators, or SARs, enter the picture. Imagine not just filtering the air around you, but having a dedicated supply of clean, breathable air delivered directly to you. That’s the fundamental promise of an SAR.
  Allegro Industries 9220‐01 1-Worker Tyvek Hood System, 50' Hose, Standard

The SAR Promise: Your Personal Bubble of Clean Air

Unlike Air-Purifying Respirators (APRs) which filter the surrounding air, SAR systems take a different approach: they supply air from an independent, known clean source. Think of it as the difference between cleaning the water from a muddy puddle versus having fresh water piped in from a clean spring.

One of the key scientific principles behind many SARs, especially those with hoods like the one we’ll discuss, is positive pressure. Imagine trying to blow dust into a box that has a fan inside constantly blowing air outwards through small openings. It’s difficult, right? The outward airflow creates a barrier. Positive pressure respirators work similarly. By maintaining a slightly higher air pressure inside the hood or facepiece than the surrounding environment, they create a continuous outflow of air through any small gaps. This outflow acts like an invisible shield, significantly reducing the chance of contaminated air leaking inwards.

The Allegro Industries 9220‐01 system is a specific type of SAR known as an Ambient Air Pump SAR. Instead of relying on heavy compressed air tanks or complex airline systems, it uses a pump to draw in air from the immediate surroundings – the “ambient” air – and deliver it to the worker through a hose. This design offers certain advantages in portability and simplicity, but as we’ll see, it also comes with a critical requirement.

Powering the Bubble: The Ambient Air Pump

The heart of the Allegro 9220-01 system is its electric pump. The term “Ambient Air” is key here. This pump doesn’t purify the air it takes in; it simply moves it. Therefore, the single most crucial factor for safety when using this type of system is the location of the pump’s air intake. It must be placed in an area known to be free of contaminants and with normal oxygen levels. Placing the intake in a contaminated zone would be like directing a fire hose spraying polluted water into your safe zone – utterly defeating the purpose and potentially increasing the hazard.

Inside the pump housing (described as metal with a durable powder-coated finish), an oil-less rotary vane pump likely does the work. How does this function? Picture a slotted rotor spinning inside a slightly larger, offset circular cavity. Small vanes slide in and out of the rotor’s slots, pushed against the cavity walls by rotation. As the rotor turns, the spaces between the vanes, rotor, and cavity wall continuously expand and contract. Air is drawn in where the space expands and pushed out where it contracts, creating a steady flow.

The “oil-less” designation is significant for breathing air applications. Traditional pumps might use oil for lubrication and sealing, which carries a risk of introducing oil mist or vapors into the supplied air. An oil-less design eliminates this contamination source, helping to ensure the air delivered to the user remains clean (assuming the source air is clean).

The pump is driven by a ¾ horsepower electric motor, compatible with standard 115V or 230V AC power outlets. This motor provides the necessary power to draw in sufficient air and push it through the length of the hose to the worker’s hood, overcoming the air resistance along the way. While the specific airflow rate (measured in cubic feet per minute, or CFM) for this model requires verification from the manufacturer’s official specifications, NIOSH generally requires minimum flow rates for loose-fitting hoods (often 6 CFM or higher) to ensure adequate positive pressure and air supply.

The Lifeline and the Veil: Hose and Hood

Connecting the pump to the worker is the 50-foot polyvinyl hose. This length dictates the user’s working radius from the pump’s location. Managing this “lifeline” is important during work to prevent kinks, crushing, or snagging, which could restrict airflow.

At the worker’s end is the poly-coated DuPont™ Tyvek® hood. Tyvek itself is a fascinating material, made from high-density polyethylene fibers flash-spun and bonded under heat and pressure, creating a non-woven fabric known for its barrier properties against fine particles and aerosols, while remaining relatively lightweight and breathable (though coating affects breathability). The “poly-coated” aspect likely refers to a polyethylene coating applied to the Tyvek fabric. This coating typically enhances the barrier against liquid splashes and certain chemicals, making it suitable for applications like painting where overspray or splashes might occur. However, the specific type of Tyvek and coating, and thus its precise chemical resistance profile, needs confirmation from Allegro Industries or DuPont technical data.

Unlike tight-fitting respirator masks that require a perfect seal against the face, this system uses a loose-fitting hood. This offers several practical advantages:
* Comfort: Often less restrictive and potentially cooler to wear for extended periods.
* Compatibility: Can typically accommodate facial hair, glasses, and doesn’t require fit testing (a procedure needed for tight-fitting masks to ensure a proper seal).
* Protection Mechanism: Relies entirely on the sufficient flow of clean air creating positive pressure inside the hood to prevent inward leakage of contaminants.

It’s crucial to understand the protection level offered. Respiratory protection is quantified by an Assigned Protection Factor (APF), designated by NIOSH and OSHA. The APF indicates how many times cleaner the air inside the respirator is expected to be compared to the air outside, when used correctly within a complete respiratory protection program. Loose-fitting hoods, like the one likely included in this system, typically have an APF of 25 or sometimes (if certain criteria are met) 1000, according to OSHA standards. This is significantly higher than most air-purifying half-masks (APF 10) or full-facepieces (APF 50), but lower than some other types of SARs or SCBAs. Confirmation of the specific NIOSH approval and APF for the complete Allegro 9220-01 system is essential for proper selection and use.

Where It Works Best (And Where It Doesn’t): Real-World Use & Crucial Limits

Based on the description, the Allegro 9220-01 system is intended for specific scenarios: low contamination areas. Let’s visualize this:
* Painting: A worker spray-painting furniture or parts within a well-ventilated area, but still needing protection from solvent vapors and paint mist. The SAR provides a continuous supply of fresh air, overcoming the limitations of filter cartridges which can become saturated. The Tyvek hood offers protection against overspray.
* Asbestos Abatement: Perhaps during the initial setup or final cleanup phases where airborne fiber concentrations are expected to be relatively low, but respiratory protection is still mandatory. Again, the positive pressure supplied air offers a higher protection level than typical APRs.

However, the limitations are just as important as the applications:
* The Golden Rule: We must reiterate – the air intake for the pump MUST be in a verifiable clean air zone. Never place the pump inside the contaminated work area, near exhaust vents, or downwind from the contamination source. This is non-negotiable for safety.
* Not for Oxygen Deficiency: This system supplies ambient air; it does not create oxygen. Using it in an oxygen-deficient atmosphere (below 19.5% oxygen, per OSHA) would be extremely dangerous, potentially fatal.
* Not for IDLH Conditions: It is not suitable for environments deemed Immediately Dangerous to Life or Health (IDLH). IDLH atmospheres pose an immediate threat and require respirators with the highest reliability and often an independent air supply (like an SCBA or a SAR with an escape cylinder). Ambient air pump SARs generally lack the required features and backup systems for IDLH use.
* Portability Trade-offs: While it avoids air tanks, the system (pump, hose, hood, power cord) still requires setup. The listed package weight of 65 pounds suggests the pump itself is substantial, requiring consideration for transport and placement on the job site. It also requires a reliable AC power source.

Safety Isn’t Automatic: Use, Care, and Awareness

Owning the right equipment is only the first step. Safe and effective respiratory protection relies heavily on proper use, maintenance, and awareness:
* Training is Vital: Users must be trained on how the system works, its limitations, how to correctly don and doff the hood, how to position the pump intake, how to check the hose and connections before each use, and what to do in an emergency (e.g., power failure).
* Maintenance Matters: While oil-less pumps often require less maintenance than oiled ones, regular checks are still necessary. Hoses need inspection for damage or kinks. Hoods (often disposable or limited-use) need to be clean and intact. Following the manufacturer’s specific instructions for cleaning and maintenance is crucial. Accessing the official user manual for the 9220-01 is highly recommended.
* NIOSH Certification: In the United States, respiratory protection equipment used in occupational settings must be certified by the National Institute for Occupational Safety and Health (NIOSH). This certification ensures the device meets minimum performance standards when properly maintained and used. Verification of the specific NIOSH approval number (e.g., TC-19C-XXX) for the complete Allegro 9220-01 system (pump, hose, and hood combination) is paramount before workplace use. Look for the NIOSH label on the equipment components.
* Situational Awareness: Users need to be aware of their surroundings. What happens if the power cord gets unplugged or the pump fails? Because this type of system likely lacks low-flow alarms or an emergency air supply, users must have a plan to immediately leave the contaminated area if airflow stops.

Conclusion: Breathing Safer in Specific Situations

The Allegro Industries 9220‐01 1-Worker Tyvek Hood System represents a specific category of respiratory protection: an ambient air pump SAR designed for single users in environments with low levels of specific contaminants, where the air is otherwise breathable and an independent clean air source is readily available near the work zone. Its strengths lie in providing a continuous supply of fresh air via positive pressure within a comfortable, loose-fitting hood, without the need for compressed air tanks.

However, its effectiveness hinges entirely on the correct placement of the air intake and its unsuitability for oxygen-deficient or IDLH atmospheres must be respected. Like any tool, especially one critical for safety, understanding its capabilities, its profound limitations, and the procedures for its correct use and care is non-negotiable.

Ultimately, choosing the right respiratory protection involves a thorough assessment of the workplace hazards, understanding the protection factors required, and selecting certified equipment that matches the task, the environment, and the worker. The Allegro 9220-01 offers a potential solution for a specific niche, reminding us that ensuring a breath of fresh, safe air on the job often requires more than just hoping for the best – it requires knowledge, diligence, and the right, properly used equipment.