California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 4 - Construction Safety Orders › Article 4 - Dusts, Fumes, Mists, Vapors, and Gases › Appendix F - Work Practices and Engineering Controls for Class I Asbestos Operations (Non-Mandatory)

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
This is a non-mandatory appendix to the asbestos
						standards for construction and for shipyards. It describes criteria and
						procedures for erecting and using negative pressure enclosures for Class I
						Asbestos Work, when NPEs are used as an allowable control method to comply with
						subsection (g)(5)(A) of this section. Many small and variable details are
						involved in the erection of a negative pressure enclosure. OSHA and most
						participants in the rulemaking agreed that only the major, more performance
						oriented criteria should be made mandatory. These criteria are set out in
						subsection (g) of this section. In addition, this appendix includes these
						mandatory specifications and procedures in its guidelines in order to make this
						appendix coherent and helpful. The mandatory nature of the criteria which
						appear in the regulatory text is not changed because they are included in this
						"non-mandatory" appendix. Similarly, the additional criteria and procedures
						included as guidelines in the appendix, do not become mandatory because
						mandatory criteria are also included in these comprehensive guidelines.
In addition, none of the criteria, both mandatory and
						recommended, are meant to specify or imply the need for use of patented or
						licensed methods or equipment. Recommended specifications included in this
						attachment should not discourage the use of creative alternatives which can be
						shown to reliably achieve the objectives of negative-pressure
						enclosures.
Requirements included in this appendix, cover general
						provisions to be followed in all asbestos jobs, provisions which must be
						followed for all Class I asbestos jobs, and provisions governing the
						construction and testing of negative pressure enclosures. The first category
						includes the requirement for use of wet methods, HEPA vacuums, and immediate
						bagging of waste; Class I work must conform to the following provisions:
* oversight by competent person
* use of critical barriers over all openings to work
						area
* isolation of HVAC systems
* use of impermeable dropcloths and coverageof all
						objects within regulated areas
In addition, more specific requirements for NPEs
						include:
* maintenance of -0.02 inches water gauge within
						enclosure
* manometric measurements
* air movement away from employees performing removal
						work
* smoke testing or equivalent for detection of leaks and
						air direction
* deactivation of electrical circuits, if not provided
						with ground-fault circuit interrupters.
Planning the Project
The standard requires that an exposure assessment be
						conducted before the asbestos job is begun [Subsection
						1529(f)(1)] .
						Information needed for that assessment, includes data relating to prior similar
						jobs, as applied to the specific variables of the current job. The information
						needed to conduct the assessment will be useful in planning the project, and in
						complying with any reporting requirements under this standard, when significant
						changes are being made to a control system listed in the standard, [see also
						those of USEPA (40 CFR
						61, subpart M). Thus, although the standard
						does not explicitly require the preparation of a written asbestos removal plan,
						the usual constituents of such a plan, i.e., a description of the enclosure,
						the equipment, and the procedures to be used throughout the project, must be
						determined before the enclosure can be erected. The following information
						should be included in the planning of the system:
A physical description of the work area;
A description of the approximate amount of material to be
						removed;
A schedule for turning off and sealing existing
						ventilation systems;
Personnel hygiene procedures;
A description of personal protective equipment and
						clothing to be worn by employees;
A description of the local exhaust ventilation systems to
						be used and how they are to be tested;
A description of work practices to be observed by
						employees;
An air monitoring plan;
A description of the method to be used to transport waste
						material; and The location of the dump site.
Materials and Equipment Necessary for Asbestos Removal
						Although individual asbsetos removal projects vary in terms of the equipment
						required to accomplish the removal of the materials, some equipment and
						materials are common to most asbestos removal operations.
Plastic sheeting used to protect horizontal surfaces,
						seal HVAC openings or to seal vertical openings and ceilings should have a
						minimum thickness of 6 mils. Tape or other adhesive used to attach plastic
						sheeting should be of sufficient adhesive strength to support the weight of the
						material plus all stresses encountered during the entire duration of the
						project without becoming detached from the surface.
Other equipment and materials which should be available
						at the beginning of each project are:
-- HEPA Filtered Vacuum is essential for cleaning the
						work area after the asbestos has been removed. It should have a long hose
						capable of reaching out-of-the-way places, such as areas above ceiling tiles,
						behind pipes, etc.
-- Portable air ventilation systems installed to provide
						the negative air pressure and air removal from the enclosure must be equipped
						with a HEPA filter. The number and capacity of units required to ventilate an
						enclosure depend on the size of the area to be ventilated. The filters for
						these systems should be designed in such a manner that they can be replaced
						when the air flow is reduced by the build-up of dust in the filtration
						material. Pressure monitoring devices with alarms and strip chart recorders
						attached to each system to indicate the pressure differential and the loss due
						to dust buildup on the filter are recommended.
-- Water sprayers should be used to keep the asbsetos
						material as saturated as possible during removal; the sprayers will provide a
						fine mist that minimizes the impact of the spray on the material.
-- Water used to saturate the asbestos containing
						material can be amended by adding at least 15 milliliters ( ¼ ounce) of
						wetting agent in 1 liter (1 pint) of water. An example of a wetting agent is a
						50/50 mixture of polyoxyethylene ether and polyoxyethylene polyglycol
						ester.
-- Backup power supplies are recommended, especially for
						ventilation systems.
-- Shower and bath water should be with mixed hot and
						cold water faucets. Water that has been used to clean personnel or equipment
						should either be filtered or be collected and discarded as asbestos waste. Soap
						and shampoo should be provided to aid in removing dust from the workers' skin
						and hair.
-- See subsections (h) and (i) of this section for
						appropriate respiratory protection and protective clothing.
-- See subsection (k) of this section for required signs
						and labels. Preparing the Work Area
Disabling the HVAC Systems: The power to the heating,
						ventilation and air conditioning systems that service the restricted area must
						be deactivated and locked off. All ducts, grills, access ports, windows and
						vents must be sealed off with two layers of plastic to prevent entrainment of
						contaminated air.
Operating HVAC Systems in the Restricted Area: If
						components of a HVAC system located in the restricted area are connected to a
						system that will service another zone during the project, the portion of the
						duct in the restricted area must be sealed and pressurized. Necessary
						precautions include caulking the duct joints, covering all cracks and openings
						with two layers of sheeting, and pressurizing the duct throughout the duration
						of the project by restricting the return of air flow. The power to the fan
						supplying the positive pressure should be locked "on" to prevent pressure
						loss.
Sealing Elevators: If an elevator shaft is located in the
						restricted area, it should be either shut down or isolated by sealing with two
						layers of plastic sheeting. The sheeting should provide enough slack to
						accommodate the pressure changes in the shaft without breaking the air-tight
						seal.
Removing Mobile Objects: All movable objects should be
						cleaned and removed from the work area before an enclosure is constructed
						unless moving the objects creates a hazard. Mobile objects will be assumed to
						be contaminated and should be either cleaned with amended water and a HEPA
						vacuum and then removed from the area or wrapped and then disposed of as
						hazardous waste.
Cleaning and Sealing Surfaces: After cleaning with water
						and a HEPA vacuum, surfaces of stationary objects should be covered with two
						layers of plastic sheeting. The sheeting should be secured with duct tape or an
						equivalent method to provide a tight seal around the object.
Bagging Waste: In addition to the requirement for
						immediate bagging of waste for disposal, it is further recommended that the
						waste material be double-bagged and sealed in plastic bags designed for
						asbestos disposal. The bags should be stored in a waste storage area that can
						be controlled by the workers conducting the removal. Filters removed from
						handling units and rubbish removed from the area are to be bagged and handled
						as hazardous waste.
Constructing the Enclosure
The enclosure should be constructed to provide an
						air-tight seal around ducts and openings into existing ventilation systems and
						around penetrations for electrical conduits, telephone wires, water lines,
						drain pipes, etc. Enclosures should be both airtight and watertight except for
						those openings designed to provide entry and/or air flow control.
Size: An enclosure should be the minimum volume to
						encompass all of the working surfaces yet allow unencumbered movement by the
						worker(s), provide unrestricted air flow past the worker(s), and ensure walking
						surfaces can be kept free of tripping hazards.
Shape: The enclosure may be any shape that optimizes the
						flow of ventilation air past the worker(s).
Structural Integrity: The walls, ceilings and floors must
						be supported in such a manner that portions of the enclosure will not fall down
						during normal use.
Openings: It is not necessary that the structure be
						airtight; openings may be designed to direct air flow. Such openings should be
						located at a distance from active removal operations. They should be designed
						to draw air into the enclosure under all anticipated circumstances. In the
						event that negative pressure is lost, they should be fitted with either HEPA
						filters to trap dust or automatic trap doors that prevent dust from escaping
						the enclosure. Openings for exits should be controlled by an airlock or a
						vestibule.
Barrier Supports: Frames should be constructed to support
						all unsupported spans of sheeting.
Sheeting: Walls, barriers, ceilings and floors should be
						lined with two layers of plastic sheeting having a thickness of at least 6
						mil.
Seams: Seams in the sheeting material should be minimized
						to reduce the possibilities of accidental rips and tears in the adhesive or
						connections. All seams in the sheeting should overlap, be staggered and not be
						located at corners or wall-to-floor joints.
Areas Within an Enclosure: Each enclosure consists of a
						work area, a decontamination area, and waste storage area. The work area where
						the asbestos removal operations occur should be separated from both the waste
						storage area and the contamination control area by physical curtains, doors,
						and/or airflow patterns that force any airborne contamination back into the
						work area.
See subsection (j) of this section for requirements for
						hygiene facilities.
During egress from the work area, each worker should step
						into the equipment room, clean tools and equipment, and remove gross
						contamination from clothing by wet cleaning and HEPA vacuuming. Before entering
						the shower area, foot coverings, head coverings, hand coverings and coveralls
						are removed and placed in impervious bags for disposal or cleaning. Airline
						connections from airline respirators with HEPA disconnects and power cables
						from powered air-purifying respirators (PAPRs) will be disconnected just prior
						to entering the showering room. Establishing Negative Pressure Within the
						Enclosure
Negative Pressure: Air is to be drawn into the enclosure
						under all anticipated conditions and exhausted through a HEPA filter for 24
						hours a day during the entire duration of the project.
Air Flow Tests: Air flow patterns will be checked before
						removal operations begin, at least once per operating enclosure. The primary
						test for air flow is to trace air currents with smoke tubes or other visual
						methods. Flow checks are made at each opening and at each doorway to
						demonstrate that air is being drawn into the enclosure and to each worker's
						position to show that air is being drawn away from the breathing zone.
Monitoring Pressure Within the Enclosure: After the
						initial air flow patterns have been checked, the static pressure must be
						monitored within the enclosure. Monitoring may be made using manometers,
						pressure gauges, or combinations of these devices. It is recommended that they
						be attached to alarms and strip chart recorders at points identified by the
						design engineer.
Corrective Actions: If the manometers or pressure gauges
						demonstrate a reduction in pressure differential below the required level, work
						should cease and the reason for the change investigated and appropriate changes
						made. The air flow patterns should be retested before work begins again.
Pressure Differential: The design parameters for static
						pressure differentials between the inside and outside of enclosures typically
						range from 0.02 to 0.10 inches of water gauge, depending on conditions. All
						zones inside the enclosure must have less pressure than the ambient pressure
						outside of the enclosure (-0.02 inches water gauge differential). Design
						specifications for the differential vary according to the size, configuration,
						and shape of the enclosure as well as ambient and mechanical air pressure
						conditions around the enclosure.
Air Flow Patterns: The flow of air past each worker shall
						be enhanced by positioning the intakes and exhaust ports to remove contaminated
						air from the worker's breathing zone, by positioning HEPA vacuum cleaners to
						draw air from the worker's breathing zone, by forcing relatively uncontaminated
						air past the worker toward an exhaust port, or by using a combination of
						methods to reduce the worker's exposure.
Air Handling Unit Exhaust: The exhaust plume from air
						handling units should be located away from adjacent personnel and intakes for
						HVAC systems.
Air Flow Volume: The air flow volume (cubic meters per
						minute) exhausted (removed) from the workplace must exceed the amount of makeup
						air supplied to the enclosure. The rate of air exhausted from the enclosure
						should be designed to maintain a negative pressure in the enclosure and air
						movement past each worker. The volume of air flow removed from the enclosure
						should replace the volume of the container at every 5 to 15 minutes. Air flow
						volume will need to be relatively high for large enclosures, enclosures with
						awkward shapes, enclosures with multiple openings, and operations employing
						several workers in the enclosure.
Air Flow Velocity: At each opening, the air flow velocity
						must visibly "drag" air into the enclosure. The velocity of the air flow within
						the enclosure must be adequate to remove airborne contamination from each
						worker's breathing zone without disturbing the asbestos-containing material on
						surfaces.
Airlocks: Airlocks are mechanisms on doors and curtains
						that control the air flow patterns in the doorways. If air flow occurs, the
						patterns through doorways must be such that the air flows toward the inside of
						the enclosure. Sometimes vestibules, double doors, or double curtains are used
						to prevent air movement through the doorways. To use a vestibule, a worker
						enters a chamber by opening the door or curtain and then closing the entry
						before opening the exit door or curtain.
Airlocks should be located between the equipment room and
						shower room, between the shower room and the clean room, and between the waste
						storage area and the outside of the enclosure. The air flow between the
						adjacent rooms must be checked using smoke tubes or other visual tests to
						ensure the flow patterns draw air toward the work area without producing
						eddies.
Monitoring for Airborne Concentrations
In addition to the breathing zone samples taken as
						outlined in subsection (f) of this section, samples of air should be taken to
						demonstrate the integrity of the enclosure, the cleanliness of the clean room
						and shower area, and the effectiveness of the HEPA filter. If the clean room is
						shown to be contaminated, the room must be relocated to an uncontaminated
						area.
Samples taken near the exhaust of portable ventilation
						systems must be done with care.
General Work Practices
Preventing dust dispersion is the primary means of
						controlling the spread of asbestos within the enclosure. Whenever practical,
						the point of removal should be isolated, enclosed, covered, or shielded from
						the workers in the area. Waste asbestos containing materials must be bagged
						during or immediately after removal; the material must remain saturated until
						the waste container is sealed.
Waste material with sharp points or corners must be
						placed in hard airtight containers rather than bags.
Whenever possible, large components should be sealed in
						plastic sheeting and removed intact.
Bags or containers of waste will be removed to the waste
						holding area, washed, and wrapped in a bag with the appropriate labels.
Cleaning the Work Area
Surfaces within the work area should be kept free of
						visible dust and debris to the extent feasible. Whenever visible dust appears
						on surfaces, the surfaces within the enclosure must be cleaned by wiping with a
						wet sponge, brush, or cloth and then vacuumed with a HEPA vacuum.
All surfaces within the enclosure should be cleaned
						before the exhaust ventilation system is deactivated and the enclosure is
						disassembled. An approved encapsulant may be sprayed onto areas after the
						visible dust has been removed.
1. New
						Appendix F to section
						1529 filed 2-15-91; operative
						2-15-91 pursuant to Government Code section
						11346.2(d)
						(Register 91, No. 19).
2. Editorial correction of HISTORY 1.
						(Register 91, No. 45).
3. Repealer and new appendix and NOTE filed
						5-3-96; operative 7-3-96 (Register 96, No. 18).
Note: Authority cited: Section
						  142.3, Labor
						  Code. Reference: Section
						  142.3, Labor
						  Code.