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I. Introduction to Plastic Containment Barriers
Purpose: To isolate and control environments during water damage, demolition, and mold remediation projects.
Material: Typically 4-6 mil polyethylene (poly) sheeting, with 6 mil preferred for mold remediation.
Construction: Barriers can be erected using:
Painter's tape and duct tape
Spray adhesive
Tension poles
Wooden frames with stapled plastic
PVC pipe frames
Key Considerations:
Durability based on project type and traffic.
Occupant safety and accessibility.
Fire retardant materials in commercial settings.
II. Types of Containment Based on Project Type
Water Damage Projects:
Zone Barrier: Maintains ideal temperature and humidity within the work area.
HVAC Integration: HVAC returns should always be included within the barrier to better control temperature.
Zoning: Barriers can create separate zones based on water damage class (e.g., Class 1 vs. Class 2 or 3).
Ceiling and wall considerations: open ceilings and walls must be covered to avoid atmospheric contamination.
Demolition Projects:
Dust Barrier: Prevents excessive dust spread.
Protection: Covers cabinets, furniture, and walls.
Material Variation: 4-6 mil for work areas, painter's plastic for coverings.
Mold Remediation Projects:
Containment: Prevents the spread of mold spores.
Material: Always 6 mil poly.
Egress: May or may not include egress from the primary work area.
III. Mold Remediation Containment Types
Source Containment:
Directly covers contaminated building materials.
Temporary measure until more robust containment is established.
Putting plastic & tape over visible mold growth on drywall, while waiting on approval to build a full localized containment.
Local Containment:
Isolates a small affected area from a larger, unaffected area.
Isolating the kitchen from the remaining area of the structure.
Full Containment:
Encompasses a large area of a structure, if not the entire structure.
There is very little to no area within the structure that is not having remediation work performed.
Primary Containment:
This is the containment where the work is to be performed.
This is the contaminated area.
Secondary Containment:
This is the area outside of the primary containment.
This is the unaffected or uncontaminated area of the property.
Decontamination Containments:
Equipment Room/Clean Room/Airlock Chamber: Small rooms for:
Trash preparation (vacuuming, bagging, sealing).
PPE donning and equipment preparation.
Size: Typically 3x3 to 10x10 feet.
Critical Barrier:
This is plastic put over potential sources of air intrusion which would complicate the remediation efforts.
HVAC registers
Sewer & drain openings
switch & outlets
Intended to remain in place until the project is completed.
IV. Construction of Containment Support Structures
Support Skeleton:
Provides a framework for attaching plastic.
Essential for negative pressure environments.
Materials:
2x4 or 2x3 framing
Tension poles
PVC pipe
Plastic attachment systems for dropped ceilings.
Interference Fit Wood:
2x4 or 2x3 lumber cut tightly to fit in doorways or large openings.
Held in place by friction.
Plastic is stapled or button capped.
Rolled foam is used to protect sensitive surfaces and create an airtight fit.
Tension Poles:
Spring-loaded assemblies that hold plastic between the ceiling and floor.
Quick to construct and dismantle.
Less durable; not suitable for all situations, can generally not sustain a strike without failure.
PVC Pipe:
1-inch PVC pipe and fittings friction-fit to create a self-supporting frame.
More stable than tension poles, less durable than wood framing.
Double sided tape is useful for bonding the plastic to the PVC pipe skeleton.
Plastic sheeting must be on the outside of the PVC skeleton.
there are plastic attachment systems designed for piping that may assist in construction.
Plastic Attachment Systems for Dropped Ceilings:
Plastic version clamps to the ceiling grid & grips the barrier plastic with a bayonet & retainer.
There's a version that attaches to piping that allows a bayonet & retainer to hold barriers to pipes.
Metal version slips behind or over the top of the support channel at the wall. Plastic is held in place by piercing the plastic over a sharp wedge.
These systems require further reinforcement from tension poles as these systems can't support negative pressure without collapsing.
They also don't really support entry systems either.
There are several different types of plastic hangers designed to support plastic for containment structures.
V. Attachment and Fitment of Plastic to Structures
Tape Types:
Duct Tape: Fabric backed water resistant pressure sensitive adhesive that's Ideal for bonding plastic-to-plastic, but less effective on drywall.
HVAC Tape: fabric backed with a stronger adhesive designed for high-temperature and cold temperature resistance. It will damage finished surfaces it's applied to.
Foil Tape: aluminum backed, strong solvent based adhesive, damages most surfaces it's applied to.
Double-Sided Tape: A fabric backed pressure sensitive adhesive that's double sided. It's an excellent choice for use bonding plastic-to-plastic and plastic-to-painter's tape bonds.
Spray Adhesive: Best for bonding plastic-to-plastic as it damages painted surfaces.
Painter's Tape: A paper backed, pressure sensitive adhesive that bonds well to painted drywall, should be used as a base for duct tape. The adhesive strength varies from product to product.
Sheathing Tape: Also known as "Tuck" tape, is a strong polypropylene tape with solvent adhesive that will tear plastic & will not peel loose once attached.
Preservation Tape: Vinyl backed tape with pressure sensitive adhesive that doesn't typically leave residue behind if used in short amounts of time.
Staples:
Durable connection, but creates damage that will require repair. Staples must be pulled, holes patched, and casings repainted.
By folding over plastic or using cardboard squares to increase surface area of a staple, it makes for added containment durability.
Staple to the exterior flat side of the door casing versus the detailed face, as this is the easier surface to repair.
Button Caps:
Creates a more durable bond when attaching plastic to wood framing.
VI. Egress Points and Zippers
Egress Points:
The entry point to the contaminated area.
Generally facilitated by a inverted "T" cut into the plastic.
Inverted T is laid out with durable duct tape as reinforcement to the plastic to avoid damage to the plastic.
Top of the vertical line is 3-6" from the top of the plastic or about 6'3 to 6'5 from the floor. an extra 3-4" strip of tape should be laid over the top of the vertical line for additional reinforcement.
Bottom horizontal line is 3" from the floor and should be 2-3' wide, centered on the vertical line. Slightly overlapping the vertical line. The far left & right side of the horizontal strip should be reinforced with 3-4" of extra tape.
After tape has been adhered, using a brand new razor blade, cut through the center of the tape carefully about 2" from the top of the tape on the vertical line, to the overlapping horizontal line at the bottom. Staying to the left about 2" cut from the left side to the center, then do the same on the right side.
Flap Egress:
"T" flap: This is the simplest and most common containment entry point flap.
A extra sheet of plastic should be cut to fit across the outside of the flap to keep the area under negative pressure.
This flap is to be mounted across the top of the containment opening on the outside of the containment. & about 1/2 to 3/4 down one side.
The side is selected based on ease in entering and exiting the containment. If entering the barrier is going to be from the right side, then affix the flap onto the left side. This forces workers to go in through the right side.
The bottom of the flap needs to be weighted & semi rigid. a dowel, or even a cardboard poly tube works to prevent the flap from being drawn into the containment due to the negative pressurization.
Issue / Limitation with T flaps is that if the pressurization suddenly shifts due to a failure of the mechanical controls (ie: the negative air machines shut down, during a wind event, the containment can find itself positively pressurized. This containment strategy can push open the flap & allow particulate to escape into an unaffected area.
"Z" flap: This is a more complex containment entry point in both construction & use, but remedies the issue with a T flap pressurization.
Construction is the same as the T flap, however, it adds an additional flap on the interior side of the egress point.
The interior flap will be adhered on the opposite side relative to the outside flap.
This makes entering & exiting more challenging for workers, is more likely to require constant repair.
If pressurization shifts from negative to positive, the pressure will push the inside flap against the plastic, limiting the amount of air escaping.
Zippers:
Adhesive-backed, heavy-duty disposable zippers.
Installed vertically on plastic sheeting.
Used in conjunction with inverted T-cuts and flaps. (Zipper is adhered, then the inverted "T" is cut int he plastic)
Magnetic reusable zippers are available.
Use of zippers or magnetic closures do not remove the need for a "flap" to be adhered to the outside of the containment in negative pressure applications, or a "Z" flap (flaps on both sides of the inverted T.) on neutral pressure applications.
Zippers require a horizontal line to be cut about 3" from the floor, to allow egress. WIthout the flap, the containment is compromised at this horizontal cut.
VII. Containment Pressurization
Manometer Setup:
Without a manometer there's no way of determining what the negative pressure is.
The visible test of slightly collapsed containment plastic doesn't provide adequate validation that the containment is under the ideal amount of negative pressure.
The manometer unit must be leveled, with the hoses at equal height.
Measures the pressure differential between the primary containment & the secondary containment.
Neutral Pressure: No air enters or exits the structure "Scrubbing air" - Or equal amounts enter & exit.
Used when:
Outdoor contamination is a concern.
Dust-generating activities are complete.
Benefits:
Easy temperature and humidity control.
More effective air filtration.
Less outdoor infiltration of non-ideal conditions.
Negative Pressure: More air is evacuated than returns.
Negative pressurization can be achieved in the primary containment several ways:
Primary containment negative, secondary containment slightly negative, building very slightly negative. (AFD exhausted to exterior of envelope)
This is the most traditional means of achieving negative pressure. It can be too complicated to implement.
There may be an issue with security &/or a rain intrusion risk.
There may not be any suitable envelope openings in the primary containment to allow exhausting the AFD.
Primary containment negative, secondary containment positive, building neutral. (AFD exhausted into the secondary containment.)
This typically requires a 2nd AFD running neutral in the secondary containment.
Manometer reading: 0.2-0.4 inches of water column in primary containment.
Negative air is typically used during dust-generating activities.
"The solution to pollution is dilution" negative air pressure brings in a flow of cleaner outside air in to keep the particulate in the air clear.
Having the exhaust ducted prevents particulate being made airborn by intentional or accidental manipulation of the AFDs used on a project. (the exhaust blowing across a debris pile can make a giant mess)
Limitations:
Negative pressure will not control liquid migration from leaks or high-pressure air forced contaminants such as during media blasting activities.
May draw in air that's potentially more contaminated than the primary containment air, especially after dust generating activities are completed.
It's hard to control where the makeup air comes from.
Considerations:
Must take into consideration where the make-up air is going to be coming from.
Security can be a risk if exhaust isn't hardened.
Temperature & humidity associated with makeup air can cause complications.
Rain intrusion is a problem if the exhaust is not properly water proofed.
Ducting types used for negative air:
Lay flat ducting is the most widely used option, essentially a 4 or 6 mil tube on a roll.
Wire reinforced mylar which was the most commonly used ducting used, it's reusable, but is prone to failure.
Wire reinforced PVC is the most durable & reusable of the options, also exceedingly expensive to use.
Make up air considerations.
Make up air should be filtered and the source should be high on the containment if possible.
Make up air filtration is typically the same size filter used in the AFDs setup exhausting.
ie: if (2) HEPA 500s are used with 16x16 pleated filters, both exhausted to the outside, then the make up air should be through (2) 16x16" filters.
Filters are typically duct taped to the containment plastic with holes cut into the plastic to allow air to pass through the filters.
Flaps are cut & installed, secured on the interior side of the containment over the filters to provide protection against pressurization failures.
Positive Pressure: More air enters than is exhausted.
Used to keep areas free of contaminants (e.g., hospitals with immune compromised patients).
Never used in contaminated spaces.
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