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Historic Preservation - Technical Procedures

Spectitle:

Removing Paint From Wood Features Using Thermal Methods

Procedure code:

0640009R

Source:

Hspg Prepared For Nps - Sero

Division:

Wood And Plastics

Section:

Architectural Woodwork

Last Modified:

04/11/2014

Details:

Removing Paint From Wood Features Using Thermal Methods


Removing Paint From Wood Features Using Thermal Methods

Procedure code: 0640009R

 REMOVING PAINT FROM WOOD FEATURES USING THERMAL METHODS

CAUTION: PAINT MAY CONTAIN LEAD, AND SURFACES SHOULD BE TESTED FOR LEAD CONTENT IN ADVANCE OF WORK.  IF THE TEST IS POSITIVE AND YOU ARE NOT EPA CERTIFIED TO HANDLE LEAD-ABATEMENT TASKS IT IS ILLEGAL FOR YOU TO PERFORM FURTHER WORK. REGULATIONS PROVIDED BY THE EPA REGIONAL OFFICE AND/OR THE STATE OFFICE OF ENVIRONMENTAL QUALITY CONCERNING THE HANDLING OF LEAD-BASE PAINT MUST BE FOLLOWED. See http://www2.epa.gov/lead/renovation-repair-and-painting-program

The regulations limiting lead in coatings may be even more stringent in certain localities.  You need to properly research pertinent standards before utilizing any such product.  Regulatory information as well as recommendations for alternative or equivalent chemicals may be requested from the Environmental Protection Agency (EPA) Regional Office and/or the State Office of Environmental Quality.

Paint removal utilizing thermal methods can release lead fumes into the air, and inhalation of that vapor can cause lead poisoning through inhalation.  Children nearby are particularly susceptible to very low doses. The higher the temperature used to heat the paint, the greater the risk, so the lowest temperature method possible should be utilized.

PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing paint from interior and exterior wood features using thermal methods.

    B.   In general, high-heat methods should not be used in a way so as to come into contact with window glass, if at all possible.  Glass should be removed to a safe storage place to be reinstalled at a later date.  If the glass is not to be removed, it needs to be protected from sudden temperature changes which can cause breakage:  piece of gypsum board wrapped in aluminum foil can protect the glass from rapid temperature changes seen when using high-heat methods. 

    C.   Safety Precautions:

         1.   OId paint layers will likely contain lead and you must test for its presence using a certified method (test swab) or a laboratory. Again, as stated in the caution above in ALL CAPITAL LETTERS, if there is lead, you must be EPA certified to do this work.  You must use the appropriate safety precautions and Personal protective Equipment (PPE) such as gloves, goggles and respirators rated for this work. You must use proper ventilation and residue disposal procedures. 

        2.   No food or drink shall be allowed near any work station so as to prevent contamination from paint, paint chips or dust which could contain lead and other toxic substances.

         3.   Protective clothing shall be removed at the end of each day and kept at the site to prevent workers from tracking dust and paint chips to other parts of the site or to their homes.

         4.   Wash hands and face often, especially before eating and at the end of the day.

    D.   See 01100-07-S for general project guidelines to be reviewed along with this procedure.  These guidelines cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         These guidelines should be reviewed prior to performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO).

    E.   See also 06400-02-S for supplemental information on removing paint from wood features.

    F.   For additional information on the history and properties of paint along with general procedures for paint removal, see 09900-01-S, "Preservation Brief 28, Painting Historic Interiors", and 09910-01-S, "Preservation Brief 10, Exterior Paint Problems on Historic Woodwork".

1.02 REFERENCES

    A.   AWI Quality Standard:  Comply with applicable requirements of "Architectural Woodwork Quality Standards" published by the Architectural Woodwork Institute (See www.awinet.org), except as otherwise indicated.

1.03 DEFINITIONS

    A.   Thermal Methods:  These can be classified as high heat (using a traditional heat plate or heat gun), or lower heat (using a special quartz lamp equipment or a steam generation device).  In all circumstances the lowest heat needed to satisfactorily complete the work should be used as it poses the lowest risk for spreading hazardous substances.

1. It should be noted that the heat plate device mentioned above is no longer being sold by its former manufacturers, Warner or Hyde.  Any of these units still in service should be carefully inspected for faults and treated with extreme caution, utilizing the original manufacturer���������s specifications and instructions.

    B.   OPEN FLAME BLOW TORCHES ARE EXTREMELY HAZARDOUS HIGH-HEAT DEVICES.  THEY CAN VAPORIZE AND DISTRIBUTE HAZARDOUS PAINT CHEMICAL FUMES INSTANTLY.  THEY CAN CAUSE A JOBSITE FIRE WHICH CAN QUICKLY GET OUT OF CONTROL. OPEN FLAME BLOWTORCHES ARE NOT RECOMMENDED AND SHOULD NOT BE USED.

PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.    For Heat Gun:

         1.   Master Appliance Corporation      http://www.masterappliance.com

    B.  For Infrared Quartz Heater:

            1.   Eco-Strip Co       http://www.eco-strip.com

       C: Steam Generation Device:

            1. McCulloch Steam Company, Item MC1275     www.mccullochsteam.com

        D: Scraping tools

            1. Hyde Industrial Blade Solutions      www.hydetools.com

            2. Red Devil Inc.     www.reddevil.com

            3. C.S. Osborne & Co.      http://www.csosborne.com/scrapers.htm

2.02 EQUIPMENT

    A.   Electric Heat Gun such as the Master Appliance Company Model HG-201A (traditionally the higher-heat Model HG-501A had been recommended in the past)      

             1.   Heavy duty heat gun with metal case.

             2.   Operating temperature between 200 to 300 degrees F (the traditional model HG-501A operates at 500 to 700 degrees F).

             3.   The heat gun heats a much small area. The danger in using a heat gun is twofold:  The higher-temperature models can ignite dust, birds' nests, or other debris within a wall cavity or behind a cornice or soffit (and high-temperature dust can smolder and ignite hours later once the work crew has gone home); In addition, the higher-temperature heat gun models can easily vaporize chemicals in paint, including lead, making them easy to inhale.  Extreme caution must be taken when using heat guns,  and PPE (as described in 1.01 C. above) must be worn.

             4.   The heating elements can easily be damaged or wear out in these heat guns, and replacement elements should be kept on hand. 

            5.   Power Supply:  These devices draw approximately 15 amps of power.  Each work station is to be provided with its own temporary power supply so as not to overload other circuits.

            6.   Extension Cords:  Proper, heavy-duty extension cords are required, and should be kept to a minimum length.  Connections where the heat gun is plugged into the outlet and extension cord ends should be checked regularly during heavy use and monitored for large amounts of heat build-up accompanied by softening of the plug-ends.

 

B:   Infrared Quartz Heater such as Eco-Strip Co, Speedheater Model 1100-15

            1.   Screened cage unit with cool thermoplastic handle

2.   Operating temperature between 380 to 580 degrees F (manufacturer instructions indicate heating surface to a maximum of 275 degrees F).

3. The Speedheater heats paint in an area confined beneath its cage, making paint soft in 20 to 60 seconds.  The paint is then removed with a scraper (see D, below).

4. The quartz heating elements can easily be broken from the shock of being dropped, although improvements in the design have added ���������shock absorbers��������� to prevent inadvertent damage.  Spare heating elements should be kept on hand for repairs.

5. Power supply: These devices draw approximately 9 amps of power.  Each work station should be provided with its own temporary power supply so as not to overload other circuits.  The device by this manufacturer is UL listed, some duplicate products by others are not:  Use caution when choosing.

6.   Extension Cords:  Proper, heavy-duty extension cords are required, and should be kept to a minimum length.  Connections where the speed heater is plugged into the outlet and extension cord ends should be checked regularly during heavy use and monitored for large amounts of heat build-up accompanied by softening of the plug-ends.

7. For further information see the article at This Old House magazine found at http://www.thisoldhouse.com/toh/photos/0,,20586187_21145196,00.html

 

C.    Steam Generation Device such as the McCulloch Steam Company, Item MC1275    

            1.  This device is intended as a steam-cleaning setup, and comes with multiple attachments.

            2.  Operating temperature no greater than 212 degrees F.

            3.   The steam softens the paint film so it can be scraped away at a controlled temperature well below that which would release lead and most chemical decomposition fumes.  It reduces the risk of fire. Its use lowers residual disposal costs (in comparison to another method, chemical paint removal) and risk because very large pieces are removed, not small dust-particle sized ones.  It raises the moisture content of the wood several percent, but this should evaporate within 24 hours down to nearly the same as it was before the stripping.  The method works best on a vertical surface that allows water to run off so the area below the work should be tarped and protected because of this.

            4. Although the device is relatively foolproof, users should be aware that steam burns are quite dangerous, making appropriate PPE with heat-resistant gloves with waterproof coating an absolute must.

5.  Power supply: This device draws approximately 12.5 amps of power.  It should be provided with its own power supply so as not to overload other circuits. This piece of equipment should only be used with a circuit protected by a ground-fault interruption device.

6.   Extension Cords:  Proper, heavy-duty extension cords are required, and should be kept to a minimum length.  Connections where the steam generator is plugged into the outlet and extension cord ends should be checked regularly during heavy use and monitored for large amounts of heat build-up accompanied by softening of the plug-ends.  Because of the mixture of water and electricity in this application, care should be taken to keep all cords out of the runoff to prevent inadvertent injury.

            7.   For further information see the article in Old House Journal online at http://www.oldhousejournal.com/magazine/2006/june/Get-speed.shtml  or see the Steam Paint Removal Video at http://historichomeworks.com/hhw/video/spr-video.htm or at http://interior-design.wonderhowto.com/how-to/steam-remove-paint-160217/

 

D.   A variety of putty knives and paint scrapers of different shapes and flexibility should be on hand, and do not necessarily need to be sharp.  Corners of the tool should be ground to a rounded shape to prevent gouging wood surfaces.  A glazers chisel (such as the Red Devil #4231) or a 5-in-1 tool works well (such as the Red Devil #4861or #6251 as does a double-edged blade scraper (such as Hyde #10540).  For curved or carved surfaces, a three-corner triangular scraper (such as the Hyde Tools #10400 or Red Devil #3001) is useful.

PART 3---EXECUTION

3.01 EXAMINATION

    A.   On buildings, one of the main reasons for paint failure is excess moisture, both from internal and external sources. Before work is begun on removing the existing paint film or otherwise preparing the surface, all flashing and gutters and downspouts shall be inspected and repaired or replaced as required.  Make provisions as required for         removing excess moisture from areas of high humidity, or damage will soon return. 

    B.   All wood elements on a wooden surface to be stripped shall be carefully inspected for rot and, if deteriorated, marked for replacement after the paint has been removed.

    C.   If access can be gained, cavities behind cornices, soffits, etc. should be checked for bird's nests and other debris.

3.02 PREPARATION

    A.   Protection:

         1.   Protect adjacent surfaces, including grass, shrubs and trees with paper, drop cloths and other means.              

         2.   Items not painted which are in contact with or adjacent to painted surfaces shall be removed or protected prior to surface preparation and painting operations.

 

         3.   All waste material shall be collected at the end of each work day and disposed of in a manner consistent with local environmental regulations. It is to be considered Hazardous Waste.

         4.   Work area shall be sealed off from other areas to prevent the spread of paint dust and debris beyond the work site.

         5.   After paint removal is complete, all areas around the site shall be cleaned of all paint dust and debris, and such debris shall be properly disposed of in a manner consistent with local environmental regulations.  Vacuums used to clean up dust shall              be equipped with High Efficiency Particulate Air (HEPA) filters.

         6.   When using either thermal method, keep a fire extinguisher handy.  Work should also be stopped several hours before the day's work is completed and the job site is vacated so that smoldering fires can be detected.

3.03 ERECTION, INSTALLATION, APPLICATION

            A.   Any of these methods (heat gun, infrared quartz heater, or steam generator) will work on both large and small areas, including smaller, narrow or curved surfaces, more intricate details or moldings, small window sash parts such as the sash runs, stops, parting bead, etc., or solid wooden elements. 

B.  Place the chosen thermal device over area to be stripped and heat the paint until it begins to soften and wrinkle.  Do not let paint bubble (unless you are using the steam generator device).              

            C.   Using a scraper (whose corners have been rounded as described in 2.02 D above), scrape and remove paint.  With practice, you should be able to remove the paint in long ribbons, which is desirable for reducing disposal and exposure issues.

            D.   To remove the last traces of paint, you may choose to go over surfaces with a liquid paint remover (see 06400-07-R), or by sanding (using proper lead and hazardous materials protection and disposal techniques, as required).

            E.   For guidance on repainting wood features, see 06300-01-S, 06300-02-R and 09900-07-S.  For guidance on refinishing  wood with a varnish or stain, see 06400-10-R.

3.04 ADJUSTING/CLEANING

    A.   Upon completion of this work, all floors, walls and other adjacent surfaces that are stained, marred, otherwise damaged by work shall be cleaned and repaired and all         work and the adjacent areas shall be left in a clean and orderly condition.

    B.   All completed work shall be adequately protected from damage by subsequent building operations and effects of weather.  Protection shall be by methods recommended by the manufacturer of installed materials and as approved by the Architect.


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