how do I calculate ventilation for a confined space

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## S-15.1 REG 10 ## OCCUPATIONAL HEALTH AND SAFETY, 2020 ## Purging and ventilating of unsafe atmosphere - 18-8 (1) In addition to the requirements of section 25-11, if a concentration of a toxic, flammable or explosive substance is present or an oxygen enrichment or deficiency exists in a hazardous confined space, an employer shall ensure that the hazardous confined space is: - (a) purged and ventilated before a worker is allowed to enter the space, so that: - (i) any hazard associated with a toxic, flammable or explosive substance is reduced to the extent that is possible or eliminated; and - (ii) an oxygen content of not less than 19.5% and not more than 23% is ensured; and - (b) continuously ventilated at all times during which the worker occupies the hazardous confined space, to maintain a safe atmosphere. - (2) If ventilation is used to reduce or eliminate a hazard pursuant to subsection (1), an employer shall ensure that a competent person tests the atmosphere to determine that the confined space is safe for entry by a worker: - (a) before a worker enters the confined space; - (b) if all workers have vacated the confined space, before any worker re-enters the confined space; - (c) on the request of a worker who is required or permitted to enter the confined space; and - (d) continuously if any condition in the confined space may change and put the worker's health or safety at risk. 31 Dec 2020 c S-15.1 Reg 10 s18-8. ## Precautions if safe atmosphere not possible - 18-9 (1) If a hazardous confined space cannot be purged and ventilated to provide a safe atmosphere or a safe atmosphere cannot be maintained pursuant to section 18-8, an employer shall ensure that no work is carried on in the confined space except in accordance with the requirements of this section and section 25-11. - (2) An employer shall ensure that a competent person continuously monitors the atmosphere in a hazardous confined space. - (3) An employer shall ensure …

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## Ventilation and purging - 53 (1) If the atmospheric testing under section 52 identifies that a hazardous atmosphere exists or is likely to exist in a confined space, an employer must ensure that the confined space is ventilated, purged or both before a worker enters the confined space. - 53 (2) If ventilating or purging a confined space is impractical or ineffective in eliminating a hazardous atmosphere, the employer must ensure that a worker who enters the confined space uses personal protective equipment appropriate for the conditions within the confined space. - 53 (3) If mechanical ventilation is needed to maintain a safe atmosphere in a confined space during the work process, an employer must ensure it is provided and operated as needed. - 53 (4) If mechanical ventilation is required to maintain a safe atmosphere in the confined space, the employer must ensure that - (a) the ventilation system incorporates a method of alerting workers to a failure of the system so that workers have sufficient time to safely leave the confined space, and - (b) all workers within the confined space have received training in the evacuation procedures to be used in the event of a ventilation system failure. - 53 (5) All workers must evacuate a confined space or use an alternative means of protection if a ventilation system fails. ## Inerting 54 (1) An employer must ensure that a confined space is inerted if it is not reasonably practicable to eliminate an explosive or flammable atmosphere within the confined space through another means. - 54 (2) If a confined space is inerted, an employer must ensure that - (a) every worker entering the confined space is equipped with supplied air respiratory protective equipment that complies with Part 18, - (b) all ignition sources are controlled, and - (c) the atmosphere within the confined space stays inerted while workers are inside. ## Emergency response - 55 (1) An employer must ensure that a worker does not enter or remain in a con…

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## OCCUPATIONAL HEALTH AND SAFETY, 2020 - (c) alternative means to perform the work to be performed in a confined space that will not require the worker to enter the confined space; and - (d) alterations to the physical characteristics of the confined spaces that may be necessary to ensure safe entrance to and exit from all accessible parts of each confined space. 31 Dec 2020 c S-15.1 Reg 10 s18-2. ## Avoidance of entry into hazardous confined space - 18-3 (1) If reasonably practicable, an employer shall use an alternative means to perform work that will not require a worker to enter a hazardous confined space. - (2) An employer shall take all reasonably practicable steps to prevent any unauthorized entry into the confined space. 31 Dec 2020 c S-15.1 Reg 10 s18-3. ## Requirements before confined space is entered - 18-4 (1) If a worker will be required or permitted to work in a confined space, an employer, contractor or owner shall, before requiring or permitting the worker to enter the confined space: - (a) ensure that there is a safe entrance to and exit from all accessible parts of the confined space; and - (b) make all practicable alterations to the physical characteristics of the confined space necessary to ensure a safe entrance to and exit from all accessible parts of the confined space. - (2) In making alterations pursuant to clause (1) (b), an employer shall ensure that the structural integrity of the confined space is maintained. 31 Dec 2020 c S-15.1 Reg 10 s18-4. ## Requirements before hazardous confined space is entered - 18-5 (1) Before a worker is required or permitted to enter a confined space, an employer shall appoint a competent person: - (a) to assess the hazards; - (b) if a hazardous atmosphere has been identified, to test the atmosphere of the confined space for: - (i) oxygen enrichment or deficiency; - (ii) the presence of flammable or explosive substances; and - (iii) the presence and hazardous concentration of…

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\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ - (1) Hoods . Freely movable hoods intended to be placed by the welder as near as practicable to the work being welded and provided with a rate of airflow sufficient to maintain a velocity in the direction of the hood of 100 linear feet per minute in the zone of welding when the hood is at its most remote distance from the point of welding. The rates of ventilation required to accomplish this control velocity using a 3-inch wide flanged suction opening are shown in the following table: - (2) Fixed enclosure . A fixed enclosure with a top and not less than 2 sides which surround the welding or cutting operations and with a rate of airflow sufficient to maintain a velocity away from the welder of not less than 100 linear feet per minute. [Statutory Authority: RCW 49.17.010, .040, .050, and .060. 15-24-100 (Order 15-04), § 296-24-[redacted postal code], filed 12/01/2015, effective 01/05/2016. Order 73-5, 296-24-[redacted postal code], filed 5/9/73 and Order 73-4, 296-24-[redacted postal code], filed 5/7/73.] ## WAC 296-24-[redacted postal code] Ventilation in confined spaces. - (1) Air replacement . You must adequately vent all welding and cutting operations carried on in confined spaces to prevent the accumulation of toxic materials or possible oxygen deficiency. This applies not only to the welder but also to helpers and other personnel in the immediate vicinity. All air replacing that withdrawn must be clean and respirable. - (2) Airline respirators . In such circumstances where is not impossible to provide such ventilation, you must use airline respirators or hose masks approved for this purpose by the National Institute for Occupational Safety and Health (NIOSH) under 42 CFR Part 84. - (3) Self-contained units . In areas immediately hazardou…

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Division 2 AO 2-2017 Oregon Administrative Rules Oregon Occupational Safety and Health Division ## [redacted phone] Enclosed spaces This rule covers enclosed spaces that may be entered by employees. It does not apply to vented vaults if the employer makes a determination that the ventilation system is operating to protect employees before they enter the space. This rule applies to routine entry into enclosed spaces in lieu of the confined space entry requirements contained in [redacted phone] (4) through (11). If, after the employer takes the precautions given in [redacted phone] and [redacted phone] of Division 2/RR, the hazards remaining in the enclosed space endanger the life of an entrant or could interfere with an entrant's escape from the space, then entry into the enclosed space must meet the permit-space entry requirements of [redacted phone] (4) through (11), Confined spaces, in Division 2/J. - (1) Safe work practices. The employer must ensure the use of safe work practices for entry into, and work in, enclosed spaces and for rescue of employees from such spaces. - (2) Training. Each employee who enters an enclosed space or who serves as an attendant must be trained in the hazards of enclosed-space entry, in enclosedspace entry procedures, and in enclosed-space rescue procedures. - (3) Rescue equipment. Employers must provide equipment to ensure the prompt and safe rescue of employees from the enclosed space. - (4) Evaluating potential hazards. Before any entrance cover to an enclosed space is removed, the employer must determine whether it is safe to do so by checking for the presence of any atmospheric pressure or temperature differences and by evaluating whether there might be a hazardous atmosphere in the space. Any conditions making it unsafe to remove the cover must be eliminated before the cover is removed. - Note to paragraph (4): The determination called for in this paragraph may consist of a check of the conditions that might foreseeably be …