Blower Doors

Don't Spread Lead


Kouba-Cavallo Associates Homepage

This article was written by Dr. Cavallo while he was at Argonne National Laboratory. A variation of this article appeared in the January/February, 2000 issue of Home Energy Magazine.

On August 26, 1999, the Milwaukee Department of Neighborhood Revitalization, Milwaukee Health Department, Wisconsin Energy Bureau, and DOE's Partnership of Affordable Housing conducted a test to discover whether lead contaminated dust is drawn into living spaces when a blower door is operated. It was found that no significant amounts of lead dust were pulled from behind walls or window openings.

The test was organized in response to a concern raised regarding the use of blower doors to test rehabbed homes involved in an energy efficiency component of Milwaukee's neighborhood revitalization program. The Milwaukee program rehabs between 800 and 1000 housing units each year, most of which are single family homes or two-flat wood frame residential structures. These homes are located in older neighborhoods where lead-based paint is a major public health concern.

Milwaukee Health Department having extensive experience in testing for the presence of lead-based paint was asked to participate in the test. Also participating was a staff member of a local weatherization agency. The Health Dept. chose the apartment for the test. The apartment was the upstairs unit of a wood frame two-flat, similar to many in Milwaukee's revitalization program.

The participants chose 5 sites around the apartment: two window sills, two painted horizontal surfaces next to windows, and one foot square floor surface next to an exterior wall. There was air movement around and near each test site when the blower door was operated.

The 5 sites were tested with dustwipes at the start of the test. Mary Smith of the Bureau of Public Health conducted the tests. All windows were then closed. The sites were cleaned by Ms. Smith and retested. Hector Ruiz then operated the blower door at 50 Pascals for 10 minutes. We checked the apartment to see if air was moving in through perimeter walls. We found air moving through outlets, around windows, and in other normal sites. Mr. Ruiz agreed with the characterization that the apartment was not tight and could benefit from air sealing measures.

After turning off the blower door, Ms. Smith again tested the 5 sites with dustwipes. The dustwipes for each of the 3 tests at each of the 5 sites were sent to the Bureau of Public Health Laboratory and tested. All sites showed lead dust levels below EPA clearance levels (as given in "Guidelines for the Evaluation and Control of Lead-Based Paint Hazards in Housing", p. 15-10). Sharon Pendleton, the project coordinator at the Health Department, characterized the test results as showing "very little lead dust impact" in the dustwipe that showed the highest reading on the final test. She said further that she believes "that this is not likely to be a fluke since the suction/draft created during such tests are not likely to disturb dust that much."

The test results (micrograms/sq.ft.) are as follows:




Post Blower

Kitchen Sill




Kitchen Radiator Cover




Kitchen Floor




Parlor Sill




Parlor Radiator Cover






Though this is but one test, it does offer support for the safety of using a blower door in older rehab projects. Moreover, it should be remembered that a blower door simulates the pressure on a building's envelope that one would find with a 20 to 25 mile per hour wind, an occurrence that is experienced commonly during storms or when weather fronts pass through.

One should also recognize that air movement through window frames and cracks in walls can be substantially limited using blower door-directed air sealing methods. Such methods can both reduce the likelihood of dust moving from behind walls and reduce unconditioned air from entering heated spaces.


For additional information, contact James Cavallo, Ph.D., Principal, at 630 971-2016 or send e-mail to

This page was last updated on May 18, 2001.