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Home  >  Confined Space Frequently Asked Questions

Confined Space Frequently Asked Questions

What is a Confined Space?

A Confined Space, in terms of OSHA and NIOSH safety requirements, refers to an area whose enclosed environment and limited access make it dangerous to workers. Confined spaces can be above or below ground level. Examples of confined spaces include pipes and sewers, crawl spaces, vents, vaults, tanks, pits, storage bins, vats and silos. Any area where access or egress is limited may be considered a confined space, especially if it is an area that can trap gasses or where an injured or impaired worker may become trapped.


How often do I need to calibrate my gas monitor?

This is a controversial subject. OSHA would have you calibrate your gas detector before each use. In practice, our customers come up with their own intervals. If the gas monitor is used infrequently, say once a month, it should be calibrated every time to give you confidence that the unit is going to respond as it should. If your company uses their detection device a few times a week, then our customers have told us they do an occasional bump test and calibrate less often.

This is consistent with information from the president of RKI Instruments, a gas detection manufacturer, who writes in an article for the National Safety Council that folks who “bump test” (subject their gas monitors to the gases they are supposed to detect in order to make sure they will register) before each use, the calibration cycle can be extended to “three to six months for instruments that successfully pass the bump gas test”.

The idea is to make sure the unit is working properly. Gas detection units are used to protect the worker's lives, so it's important to remain vigilant with upkeep and maintenance. While the gas detectors we sell at PK Safety Supply are very stable and are made for real-world work environments, calibration and bump testing with test gas are the only ways to tell the units are really working properly.

Regulatory agencies such as OSHA and ANSI often tell users to follow the manufacturer’s recommendations for calibration. But even these can be confusing. For instance, one manufacturer has a 4-gas monitor that provide an on-screen countdown from 180 days, advising users to calibrate every 6 months. However, the same company makes single-gas monitors which are supposed to be self-calibrating and last for two years; yet both the 4-gas and the single-gas monitors use the same sensors.

Add to this discussion the legal implications of the data. For readings to hold up in court as incontrovertible a monitor must calibrate both before and after each test or series of tests, as this is the only way to remove doubt as to the proper functioning of the instrument.

To create an environment of safety, it’s important to develop a routine for testing your equipment that your own safety team determines to be adequate for the protection of your workers, and make sure those standards are followed by everyone who uses a gas detector unit.

A final note: a bump test or calibration is highly recommended if an instrument has been potentially damaged or subjected to a severe condition such as sensor poisons, high gas concentrations, very high temperatures, drop or shock, etc.



"Non-Permit" and "Permit-Required" Confined Space – What’s the difference?

Workers get into trouble by not being able to recognize a confined space and their potential dangers. "Non-permit" does not mean the space is thought not to have dangers, but is a more active determination; after scrutiny, the space has been found not to contain harmful potential or actual harmful situations. A "non-permit" confined space does not contain atmosphere that is hazardous, nor is there the potential for the air to become dangerous to workers entering the site. A "non-permit" confined space has an acceptable amount of oxygen (over 19.5% and under 23.5%) and ventilation. Additionally, the area does not contain recognized hazards to workers such as machinery with moving parts, or something a worker may become engulfed in (such as a pool of liquid or an abundance of grain coming into a silo).

A "Permit-Required" confined space has at least one of the following characteristics:

(1) The space contains a hazardous atmosphere or has the potential to contain a hazardous atmosphere,
(2) The area contains a material that has the potential to engulf or overwhelm an entrant (for example grain, water, sewage, etc.),
(3) The configuration of the confined space is such that an entrant could become trapped by inwardly converging walls or asphyxiated by trapped gasses, or that has a floor that slopes downward and tapers to a smaller cross-section, or
(4) Contains any other health hazards or recognized serious safety hazard.

Signs must be posted in these areas.

Application of these regulations to a work site can be confusing. When an employee has workers enter a confined space, the employer should assume that the employees will be working in a "permit-required" confined space as described above. Until there is enough evidence to classify a confined space as “Non-Permit”, it is mandatory that procedures for “Permit-Required” space are followed.

If the employer can prove and document the numbered steps listed in the OSHA Confined Space regulations, then the employer can reclassify the permit space. To do this, the employer must prove that the only hazard posed is an actual or potentially hazardous atmosphere. Additionally, the employer needs to demonstrate that continuous forced air ventilation alone is sufficient to maintain the space safe for entry. Finally, the employer must demonstrate that he has sufficient monitoring and inspection data to support the abated hazards above.

After all hazards have been eliminated in the space, the standard allows for the employer to reclassify the permit space (see the specific regulations for full compliance).

Through the entire work phase while working in Permit or Non-Permit spaces, documentation to support all decisions made with regards to a space's classification must be complete, current, and available to all employees and site visitors. As with many OSHA standards, companies working with confined spaces need a written document for procedures and a training schedule for all employees involved in this type of work.



Do all the gas monitors meet OSHA standards for alarms?


All our gas detectors come pre-programmed to meet OSHA alarm level requirements. Many of our detectors can also be customized for specific applications



What is the difference between the BW Quattro and the MicroClip XT?


Functionally, the two units are the same: they both have four gas sensors, they are both diffusion monitors - meaning they detect the gas they are in contact with, and do not contain internal pumps to bring air from a remote location, and they both have rechargeable battery options. Some buyers are more focused on price, and the MicroClip XT works well for them. Other buyers are more interested in longevity, and the BW Quattro is physically a little larger and more robust. It is intended to last longer.



We have some confusion about entry ways to confined spaces. Would you offer some clarification on such things as trap doors and other small openings?

If you have to bend over or step up to get into the space, chances are it will be considered a confined space. For example, if you have to bend down to keep from striking your head on the top of an opening or need to step over a raised threshold, like a trap door or access panel, OSHA would consider this opening as restrictive to entry or exit.
The intent of the rules is to ensure quick exit in the event of an emergency situation. If this ability is hampered in any way, it is likely to lead to the classification of confined space. For example ventilating or heating equipment spaces such as fan chambers and return air shafts would likely not be considered confined spaces if there were a standard door entry. However, access through anything other than a standard door would reclassify the area as confined space due to the restriction to entry and exit. Same goes for a space that could contain mechanical hazards such as fan blades, chain or belt drives as well as if there were a chemical hazard in the area.



What are the Confined Space Training Requirements?*

Both The National Fire Protection Association (NFPA) and the United States Occupational Safety and Health Administration (OSHA) offer standards for confined space procedures. OSHA offers a more elaborate approach to confined space entry. Specifically OSHA recommends that confined space rescue teams be re-evaluated every year by performing simulated interventions at sites within their areas of response.

NFPA proposes that the operational capacity of each confined space rescue team be defined by three (3) levels of competency. These levels are performance-oriented and they measure the team’s preparedness and abilities against the complexity of a confined space search, rescue and recovery intervention. The following descriptions summarize the training requirement and operational capacities of each of these levels of training.

1. Confined Space “Awareness Level” Training This level represents the minimum capability of a responder who can be involved in confined space search, rescue and recovery operation. Members of a team at this level are generally not considered to be rescuers, but they can perform certain non-entry retrievals. They need to be trained in Competence of Responders to Hazardous Materials Incidents

Rescue team members trained to a confined space “Awareness Level” will be able to:

1. Recognize hazards pertaining to confined spaces 2. Evaluate existing and potentially hazardous environments 3. Identify hazards of non-entry confined space emergencies 4. Instigate and continually maintain communications with the rescue victim 5. Carry out site control and management of the scene

2. Confined Space “Operational Level” Training Responders trained to this level of capability will meet the provisions of the “Awareness Level” requirements. Additionally, team members at this level will be trained in basic trench rescue as well as intermediate rope rescue techniques. They have the ability to recognize confined space hazards, use the specialized equipment and they know the techniques necessary to effectively support and take part in a technical confined space rescue or retrieval.

The “Operational Level” of competency involves search, rescue and recovery details in permit-required confined spaces, but duties are generally carried out under the supervision of a “Technical Level” team member.

“Operational Level” capabilities include: 1. Ability to recognize acceptable entry conditions 2. Recognition of existing and potentially dangerous or hazardous conditions 3. Managing physical and psychological challenges of confined space rescue situations 4. Identify the duties of the rescue team, back-up rescue entrants, rescue attendant and rescue team leaders.

3. Confined Space “Technician Level” Training This level of training represents the additional capabilities of being able to safely and effectively coordinate, perform and supervise confined space incidents. “Technician Level” members of the team will meet the requirements of Chapter 4 of the NFPA 472 Standards for Professional Competence of Responders to Hazardous Material Incidents as well as the Confined Space “Operation Level” requirements.

“Technician Level” Capabilities Include: 1. The ability to continuously monitor and evaluate the existing and potential conditions within the rescue site. 2. The ability to ensure medical surveillance of the rescue team members. 3. The ability to plan response actions for an entry-type rescue for a confined space within a hazardous environment. 4. The ability to implement a planned response.

Both NFPA and the OSHA offer the most comprehensive operational standards and training requirements for confined space operations. The OSHA Standard 1910.146 contains requirements for practices and procedures to protect workers from the hazards of entry into permit-required confined spaces. This standard defines acceptable entry conditions that must exist in a confined space before someone can enter. The directives are performance oriented to address the proper procedures for atmospheric monitoring, lock and tag out requirements and all other additional accident prevention measures necessary for safe entry.address the proper procedures for atmospheric monitoring, lock and tag out requirements and all other additional accident prevention measures necessary for safe entry.

The NFPA Standard 1670 addresses training requirements and desired competency outcomes for Technical Rescue Teams. The NFPA recommends a training curriculum that will achieve three different levels of response capability. These are “Awareness Level”, “Operational Level” and “Technician Level”.

I am a contractor looking for a gas detector I can use while welding in a confined space. I’m looking for something simple to use & not too expensive. Should I get the single gas monitor or the multiple gas monitor?


A 4-gas confined space gas monitor is needed for welding in a confined area. There are several to choose from. The BW GasAlertMicroClipXT would probably be the least expensive and the least cumbersome.

They are very simple to use. Should you encounter any dangerous gas levels the GasAlertMicroClip XT gas sniffer will alert you three different ways: Three bright alert lights flash simultaneously with a 95dB alarm and a vibration alarm to make you aware of any hazards.


What is the largest opening that a 7-foot tripod could be used on?


We usually say a 5ft circle. If your confined space opening is larger than that, you might want to consider a Hoist Davit System like the 8518000 Advanced 5 Piece system from Capital Safety. It provides easy access to an entry hatch, and the flexibility of pivoting the hoist system, which a tripod can’t do.



If I get the GasAlertMicroClip, do I have to have the calibration kit that goes with it?


The MicroClip XT comes ready to use, but if you are in the confined space industry, or need to continue to use it over several jobs, you will be required to calibrate the unit. The BW Honeywell Gas Alert Micro Clip Deluxe Confined Space Kit is the right kit for the job as it allows you to download data as well as calibrate the monitor.

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