* Check for other potential dust traps. In addition to carpets, rugs, and mats, potential dust traps include radiators, floor grates and registers, drapes, blinds, and upholstered furnishings. These items should be included in the plan for dust removal. In rental properties some of these items may not belong to the building owner. Owners are responsible for the items they own, while residents are responsible for their own property. However, it may be in everyone's best interests to include all of these items in the dust removal plan.
4. Planning and Preparations
Once it has been determined that dust removal is an appropriate approach, the owner should determine if the dwelling unit will be occupied or vacant while the dust removal is occurring. Dust removal work may be performed by contractors, maintenance staff, or homeowners. Individuals performing the work should be properly equipped and trained in dust removal.
If dwelling units are occupied, the owner should coordinate with residents to ensure that the roles of all involved in the process are clear. The job should be organized so that dust removal work is performed in 1 day to minimize inconvenience to residents. An Interior Worksite Preparation Level 1 is almost always appropriate (see Chapter
8). Additional personnel and equipment may be required to perform simultaneous work in multiple rooms.
Role of residents. Owners should provide residents with educational materials prepared by public agencies that indicate how residents can help in removing leaded dust. The materials should indicate that residents perform the following tasks before the professional dust removal occurs:
* Wet wash all cleanable toys.
* Store all loose personal belongings in boxes, closets, or drawers to provide easy access to floors and other surfaces during dust removal.
* Remove drapes and curtains and collect any washable area rugs for cleaning. Clean or arrange for cleaning of these items and store them in sealed plastic bags. Wash blankets known to have been unprotected during renovation or remodeling activity that disturbed lead-based paint.
* Wash or dust unupholstered furniture using disposable cloths and spray polish.
* Change filters in heating and air conditioning units, except where routinely performed by the property manager.
5. Responsibilities of Owners
Owners should perform the following tasks prior to dust removal:
* Attempt to schedule dust removal when the dwelling is vacant (such as during unit turnover).
* If the unit will be occupied, notify residents of the date dust removal will occur.
* Provide a written notice/flyer from the local health agency with information on resident responsibilities for preparation and cleaning.
* Provide for the safety of occupants.
* Arrange for dust removal of wood or metal components of windows, built-in shelving, radiators, floors, porches, owner-supplied carpets and rugs, window coverings, mats, upholstered furnishings, and other dust traps.
* Provide and install cleanable “walk-off" mats at interior entryways. This will help residents control exterior leaded dust that may be tracked into the home (Roberts, 1991).
* Ensure that dust removal contractors comply with contract specifications. Large multiunit contracts may require an onsite monitor.
* Obtain written authorization from residents for dust removal where legal authority does not exist for such activity.
* Arrange for clearance examination.
6. Responsibilities of Contractors
Contractors or maintenance staff should perform the following tasks prior to and during dust removal (City of Toronto, 1990):
* Coordinate with residents and owners or managers of property.
* Cooperate with any independent, onsite inspector or risk assessor or project monitor who may be present on large, multiunit dust removal projects.
* Perform work according to contract/work specifications.
In the case where the owner's maintenance staff are performing the work, the owner is responsible for the following (otherwise the contractor is responsible):
* Ensuring that workers are properly trained and protected (see Chapter
9).
* Providing all safety and special cleaning equipment and supplies.
* Taking precautions to minimize damage to residents' belongings.
* Moving major furnishings within rooms to facilitate thorough cleaning.
* Responding to residents' questions, complaints, and concerns.
B. Methods of Dust Removal
The objective of any dust removal strategy is to provide a dwelling unit or common area in which the leaded dust levels on all horizontal surfaces are less than the clearance levels. Any cleaning method carried out by a property owner is satisfactory if it meets this performance standard and if workers and occupants are fully protected. The procedures in the following pages describe how best to meet that performance standard.
The dust removal strategy presented in this section focuses effort on horizontal surfaces and dust traps that can have accumulations of surface dust and embedded dust. Embedded dust is dust that is trapped within a fiber matrix (such as carpeting), in cracks and crevices (of wooden floors), under carpets, on greasy surfaces, or ground into surfaces. A combination of vacuuming with a HEPA vacuum and wet cleaning is recommended to remove both surface and embedded leaded dust from household surfaces. For upholstered furnishings HEPA vacuuming alone is recommended.
1. Cleaning Hard Surfaces
The standard dust removal procedure for hard surfaces and components (e.g., hardwood floors and window components) is HEPA vacuuming followed by wet cleaning with trisodium phosphate (Milar and Mushak, 1982), or a cleaner designed specifically for lead removal or an equally effective cleaner. One study found that HEPA vacuuming hard surfaces at a rate slower than 1 minute per square meter (approximately 10 square feet) did not remove substantially more leaded dust from hard surfaces than faster methods (Ewers, 1993).Therefore, no speed or time restrictions are necessary for hard surfaces (although such restrictions are appropriate for carpeted surfaces, as detailed below).
On hard surfaces HEPA vacuums should be passed over the entire surface with overlapping strokes using normal speed. Trisodium phosphate has been shown to aid in the removal of lead in dust. There is also strong anecdotal evidence that a lead-specific, strippable coating (Grawe, 1993) and a lead-specific detergent (Wilson, 1993) are at least as effective as trisodium phosphate in removing lead. These new products may in fact be more effective than trisodium phosphate, which is now banned in some areas. Any cleaning product may be used, as long as the cleaner's performance is evaluated by determining compliance with clearance criteria and lead-specific cleaning agents. Trisodium phosphate is most likely to permit easy compliance with clearance criteria, avoiding the need for repeated cleaning. Whenever a wet cleaner is used, a small area of the surface should be tested to make sure that it does not damage the surface or its coloring. If so, another wet cleaner should be used.
General work practices
* Clean from top to bottom and vacuum before wet cleaning. On multistory dwellings, start at the top level in the rear room and work in one direction toward the front (see Figure 11.15). Then repeat the process on the remaining floors in sequence. Within a room start with the highest horizontal surfaces and work down. This would typically result in the following cleaning sequence: tops of window heads, tops of sashes, mullions, and interior and exterior window sills and troughs. Clean dust traps such as radiators, followed by baseboards, and finally floors, vents/registers, and horizontal components of the ventilation ducts that can be easily reached. When practical, work from clean areas to dirty areas to minimize the spread of leaded dust to clean areas. It is usually not necessary to clean walls and ceilings for dust removal unless those surfaces have undergone paint removal or stabilization.
* When vacuuming, use crevice and brush tools where appropriate.
* If possible, place the vacuum unit on a smooth, hard surface that has been cleaned or on a clean sheet of 6-mil plastic rather than on a carpet. Vacuum exhaust, even on HEPA vacuums, can disperse dust when the exhaust airstream disturbs settled dust on a surface. A HEPA vacuum that exhausts air from the top or side rather than the bottom helps to minimize dust dispersal, making it unnecessary to use a sheet of plastic.
* Use disposable cleaning cloths or sponges. Be prepared to dispose of them during the cleaning process and replace with new ones.
* When cleaning household surfaces other than floors, the cleaning solution may be mixed in a plastic jug and poured directly onto sponges or cloths (EPA, 1992a). This procedure is designed to minimize the contamination of the cleaning solution with leaded dust. Frequently rinse the sponge/cloth in a bucket of clean water.
* For floors a two-bucket system is strongly recommended to minimize the potential for spreading leaded dust from one location to another. The cleaning solution should be mixed in one bucket; a second bucket should contain rinse water for the mophead. Frequently, at least once per room, change the rinse water in the bucket. A disposable sponge mophead with a built-in wringer (rather than a string mop) is recommended. A final cosmetic rinse is recommended using clean water or a commercial cleaning solution.
* Clean until surface dust is no longer visible. After cleaning a window or a floor, rinse with clean water using a new sponge or cloth.
* To make a cleaning solution with trisodium phosphate or other suitable detergent, mix with water according to the manufacturer's instructions for recommended concentrations. When using the cleaner (especially trisodium phosphate), wear gloves and eye protection gear and follow all manufacturer's instructions and precautions. OSHA regulations require an onsite eyewash station when using trisodium phosphate (
29 CFR 1910.151). Also, concentrated trisodium phosphate solutions can damage and discolor some surfaces.
* Where possible, clean floors underneath rugs and carpets.
* For dust removal projects in multifamily housing, a truck-mounted vacuum unit with a HEPA filter exhaust may be preferable since the exhaust stream is located outside the dwelling and therefore is not likely to disturb dust inside the dwelling.
* Remove and dispose of HEPA vacuum cleaner bags and filters offsite, according to the manufacturer's instructions, in a controlled environment capable of capturing any dust released by the procedure. If the filters need to be changed in the middle of the job, take the vacuum unit outside the house, place it on a sheet of plastic, and remove the old filter carefully. Do not change filters inside the dwelling if possible (see Figure 11.16 a–f).
2. Removal or Cleaning of Carpets or Rugs
Carpeting and large area rugs can be major traps and reservoirs of leaded dust. Dirt embedded in fibers of carpets and rugs is not easily removed by cleaning. The procedures described in this section have been shown to reduce lead levels to a limited degree. Highly effective lead removal methods have yet to be identified (Ewers, 1993; IDHW, 1991). It is not likely that any cleaning process will remove all leaded dust embedded in carpets.
The first step in carpet dust removal is to decide if the carpet is going to be cleaned onsite, removed for disposal, or removed for professional offsite cleaning. It may be preferable to dispose of carpets that are in poor condition or those known to be highly contaminated with lead.
In fact it may be more costly to clean a lead-contaminated carpet or rug than to replace it. When carpets are removed, the precautions described below should be followed to minimize the exposure of workers and residents to leaded dust.
Removal of carpets or rugs. When a carpet or rug is going to be removed from a dwelling for either disposal or offsite cleaning, the following procedure is recommended:
Mist the entire surface of the carpet to keep dust from spreading. Carefully roll up the carpet along with any padding. (If the padding is not going to be removed, clean it like an area rug.) Wrap the carpet in a sheet of plastic, seal it with tape, and remove it from the dwelling.
Because the removal of a carpet may generate significant amounts of airborne lead-contaminated dust, Interior Worksite Preparation Level 3 or 4 is recommended. If the area in which the carpet is located is not fully contained, HEPA vacuum the floor after removing the carpet so leaded dust is not tracked to other parts of the dwelling.
Cleaning area rugs. If cleaning of large area rugs is done onsite, the following steps are recommended:
* First, vacuum the pile side (the top side) with a HEPA vacuum equipped with a beater bar or agitator attachment on the vacuum head at a rate no faster than 1 minute for every 10 square feet. The purpose of the beater bar is to dislodge embedded dust (CMHC, 1992; Ewers, 1993; IDHW, 1991).
* Fold the rug in half, exposing the backing of half of the carpet. The backing of the carpet should be HEPA vacuumed without using the beater bar attachment (City of Toronto, 1990) at a rate of 1 minute per 10 square feet.
* Vacuum the exposed floor beneath the rug at normal speed and unfold the rug.
* Fold the rug in half again, exposing the backing of the other half of the carpet, and repeat the HEPA vacuuming of the bottom of the rug and the floor underneath.
* Unfold the rug.
* HEPA vacuum the pile side of the rug again using the beater bar attachment. Vacuum at a rate no faster than 2 minutes per 10 square feet.
Consideration should be given to a final cleaning step consisting of a steam cleaning of the pile side of the rug. Steam cleaning can remove additional, but limited, amounts of lead from rugs (IDHW, 1991). This cleaning can be done by the contractor, owner, or resident using commercially available equipment. For multiunit buildings consideration should be given to the use of truck-mounted cleaning equipment since it may be significantly more powerful than typical rental equipment for residential use.
Phosphate-containing detergents may be more effective than nonphosphate-containing, regular detergents when cleaning rugs (Milar and Mushak, 1982), although the new lead-specific cleaners have not yet been evaluated for carpets. If using a commercial cleaning detergent that does not contain phosphate or a lead-specific removal agent, consideration should be given to substituting a mild trisodium phosphate or lead-specific solution (less than half the recommended strength). It may be necessary to clean a small, inconspicuous area first to determine if the material is colorfast. In all cases a second cleaning with the regular commercial cleaner is recommended. New cleaners advertised as lead-specific can also be used since preliminary evidence indicates that they are successful (Grawe, 1993; Wilson, 1993).
Cleaning wall-to-wall carpeting. For cleaning wall-to-wall carpeting, the following procedure is recommended:
Vacuum carpeting with a HEPA vacuum equipped with a beater bar or agitator attachment on the vacuum head. The beater bar helps to dislodge embedded dust. The total vacuuming time recommended is at least 4 minutes per 10 square feet of carpeting (Ewers et al., 1993), divided into two segments of at least 2 minutes for each 10 square feet. The two vacuuming segments are performed in perpendicular directions. For example, the first segment may be done in an east-west direction, while the second is done in a north-south direction.
The provisions regarding steam cleaning and suitable detergents for area rugs also apply to wall-to-wall carpeting.
3. Cleaning Upholstered Furniture
The first step in dealing with upholstered furnishings is to determine if the item is going to be discarded or cleaned. It may be preferable to dispose of items that are in poor condition or known to be highly contaminated with lead.
The recommended dust removal procedure for upholstered furniture is HEPA vacuuming without steam cleaning or other wet cleaning procedures that could damage fabrics. Cloth throw covers, slipcovers, or fitted vinyl covers should be provided for all cleaned, upholstered items. This is particularly important for items at the end of their useful lives that would not hold up well under an aggressive vacuuming. A cloth cover material that can be easily removed and washed should be selected.
Upholstery surfaces should be HEPA vacuumed with three to five passes over each surface at a total rate of 2 minutes per 10 square feet.
4. Forced Air Systems and Drop Ceilings
This section provides a practical approach to dealing with these potential dust reservoirs. At the present time, it is not known whether leaded dust in forced air ducts and drop ceilings is a hazard to residents. Although one study has measured leaded dust in air ducts (city of Toronto, 1990), the results do not provide evidence that the lead is leaking out of the ducts and posing a hazard to children. If the ceilings or forced air systems contain leaded dust, they may present a hazard to maintenance or renovation workers who access them.
Where possible, return and supply air vent registers that can be easily removed should be taken out, vacuumed, and wet cleaned (see Figure 11.17). If the vent registers are sealed to the wall or floor with paint, the edges should be misted and scored to help free the vent register with a minimum of leaded-dust generation.
Air vent registers that cannot be easily removed should be vacuumed and wet cleaned in place. The horizontal surfaces in the ductwork that can be easily reached with the vacuum attachment can be cleaned. Water should not be poured down the air duct to clean the vent register; wiping with a damp sponge or mop is adequate.
Replace the air filters on heating units and air conditioners with new filters at the time of dust removal. Used filters should be placed in plastic bags and sealed prior to disposal to minimize the potential spread of leaded dust.
Leaded dust in nonforced air systems and drop ceilings is not considered a hazard to residents unless major disturbances of the ducts or ceilings are planned, such as repairs or relocations of ducts. When major disturbances of any type of duct or ceiling work are anticipated, cleaning will probably be warranted. This includes instances when forced air systems have the direction of airflow reversed during maintenance.
5. Resident Protection
To facilitate dust removal work and provide protection for occupants, only workers should be in the work area during the dust removal process. This will also help ensure that work can be completed in 1 day. The work area is defined as the room in which dust removal is occurring or where preparations are being made for dust removal. Interior Worksite Preparation Level 1 is usually adequate for dust removal unless lead-contaminated carpets or area rugs are being removed.
