The DR EPIC Helpline Questions:

What is the recommended disinfection time of a patient room that was cleaned after a COVID-positive patient has been discharged? For example, a positive patient was discharged, the room was cleaned and fogged - is the room ready for a new admission directly after, or does the room need more time to be cleared?

Date: 8/25/20

EPIC TEAM RESPONSE:  by Derrick A. Denis

The terms “disinfection,” “cleaned,” “fogged” and “cleared” were all used in the question. Each of these terms has connotations.

Below, I have outlined the key points to understanding disinfectioncleaningfogging and clearing regarding COVID-19.


  1. Disinfection means rendering some pathogens on a surface non-viable, or unable to cause disease.  For our discussion it means rendering the virus SARS-CoV2 unable to produce the disease COVID-19 in humans.
  2. All disinfectants are not effective against every pathogen, and those that can be effective against SARS-CoV2 must be used correctly or they may not be effective.
  3. Environmental Protection Agency (EPA) registered disinfectants are recommended by the DR EPIC Team because they offer the user some liability protection and because they are state of the art or best practice.
    1. There are EPA-registered disinfectants that should be used against SARS-CoV2, because they are either
      1. Specifically registered for use against SARS-CoV2, or they are
      2. Approved for use against emerging pathogens such as SARS-CoV2.
    2. As of 7-6-2020 the EPA has approved only two disinfectants as EPA-registered for use against SARS-CoV2:
      1. Lysol Disinfectant Spray (EPA Reg No. 777-99) and Lysol Disinfectant Max Cover Mist (EPA Reg No. 777-127) are the first two disinfectants to be approved for their ability to kill the virus.
      2. This is based on laboratory testing that shows the products are effective against SARS-CoV-2.
      3. The Lysol Disinfectant Sprays have a dwell time against SARS-CoV-2 (the virus that causes COVID-19) of two (2) minutes.
  1. Disinfectants must be used according to the manufacturer’s recommendations. Most include the following:
    1. Pre-cleaning – Disinfectants are more effective on clean surfaces. So all surfaces you intend to disinfect should be cleaned. EPA claims are for nonporous surfaces only. You can go “off label” and clean porous surfaces like carpet, fabric-upholstered furniture, clothing, etc., and then disinfect them, but you will not get the EPA registration claims.
    2. Concentration – If the agent is not ready-to-use (RTU), then it is usually mixed on-site from a concentration. Mixed too lean and they won’t work. Mixed too rich and they may be dangerous for the applicator.
  • Dwell time – All disinfecting agents have a dwell time or contact time, which is the amount of time a surface has to be wet with the agent applied to a cleaned surface to achieve the desired kill rate. Spraying a surface and wiping it off won’t result in the kill ratio you desire. Fogging the air will not allow the appropriate dwell time on surfaces. The same goes for use of hand sanitizer. It must be on your hands in a liquid form for a specific time or it will have reduced efficacy.


  1. Cleaning refers to the removal of soil. In the COVID-19 context it refers to the removal of viral particles and the removal of other surface dust or debris that might reduce the efficacy of applied disinfectants.
  2. Porous items are generally cleanable to a degree, but the cleaning method is dictated by the object.  Clothes and linens are generally laundered, carpets are generally steam cleaned, books are often HEPA vacuumed, etc.
  3. EPA claims are for nonporous surfaces only. You can go “off label” and clean porous surfaces like carpet, fabric-upholstered furniture, clothing, etc., and then disinfect them, but you will not get the EPA registration claims.
  4. If the cost of cleaning exceeds the cost of replacement, it is generally best to defer to replacement to end the liability stream.


  1. Fogging refers to the delivery of a disinfecting product that is in liquid form into a fine mist or aerosol.
  2. Depending on the product, the required dwell times usually range from 1 to 15 minutes.
  3. Fogging is generally not a method for applying disinfectants to a surface in response to SARS-CoV2, because they deliver such low volumes of product as not to be able to deliver a dose of disinfectant that will remain on surfaces for the required dwell time.
  4. Foggers can wet surfaces, but they take more time to adequately wet surfaces than other means of application such as wet mopping, wet wiping, airless spraying, etc.


  1. Clearing is a term that implies the room is safe or ready for occupancy by people not wearing personal protective equipment. A cleared room is one that has been cleaned, that has had disinfectants applied per the manufacturer’s specification, and that has had enough air exchange to reduce aerosolized viral loads below the concentration of concern.
  2. Cleaning can be verified in house or by third-party industrial hygienists using UV challenge stamps and ultraviolet light, ATP swabs and bioluminometers, even SARS-CoV2 swabs and RQ-PCR analysis, etc. Each method of cleaning verification has pros and cons, such as cost and time considerations.
  3. Disinfection can be verified in house or by third-party industrial hygienists using visual assessment, biological coupons, colorimetric tags, etc. Each method of disinfection verification has pros and cons, such as cost and time considerations.
  4. Air changes can be verified in house or by a or by third-party industrial hygienists by measuring air changes per hour, viewing the outside air dampener settings, confirming HEPA filtration rates, etc., and comparing those to the facility’s desired air change minimum for re-occupancy.

I said all that to say: The answer to your question “What is the recommended disinfection time of a patient room that was cleaned after a COVID positive patient has been discharged?” is going to be unique to your facility.

Do you recommend shampooing the carpet after a COVID-positive patient discharges from the room?

Date: 8/25/20

EPIC TEAM RESPONSE (by Derrick A. Denis):

  1. I have said for years that carpet is a terrible building finish for SNFs.
  2. I recognize that carpet has pros such as providing a homey perception, that it feels soft underfoot and that it absorbs sound.
  3. However, porous flooring materials are hard to clean, hard to disinfect and are a trip hazard to non-ambulatory residents.
  4. Furthermore, carpet in SNF populations is often affected by bloodborne pathogens (BBPs) and other potentially infectious material (OPIM) due to the resident’s battles with incontinence, regurgitation issues, bowel control issues and such.
  5. Lastly, disinfectants are not EPA registered for use on porous products, so you lose the protection afforded to you if the floors were nonporous.
  6. Regardless of the floor finish, if you had a COVID-19-positive resident in a room, the EPIC Team recommends cleaning with a surfactant and disinfecting all accessible surfaces during a turn over using the EPA “List N: Disinfectants for Use Against SARS-CoV-2 (COVID-19)” and/or a product EPA-registered for use against SARS-CoV2.
  7. A nonporous floor finish would also need to be cleaned and disinfected, which is much easier and offers EPA registration protection.
  8. Consider designating a few COVID-19 rooms as airborne infection isolation rooms (AIIRs) and changing carpet for hard surfaces that can be more easily addressed in future turnovers.

I said all that to say: The decision to have carpet in your facility means you must clean and disinfect carpet in your facility during a COVID-positive room turnover.

LTCF Guidance

If a patient is in the general population unit of a healthcare center and tests positive for COVID, should the patient be wearing full PPE when transferred from gen pop to the COVID unit?

Date: 8/25/20


The Maricopa County guidelines for residents who develop COVID-19 in the facility include:

Encourage residents to remain in their room and restrict movement except for medically necessary purposes. If residents leave their room, residents should wear a surgical facemask, perform hand hygiene, limit their movement in the facility, and perform social distancing (stay at least 6 feet away from others).”

So, YES, at minimum a surgical facemask should be worn by the resident/patient.

If a dialysis resident has an outdoor visit, what type of PPE do they need to wear outdoors to the visit – reverse isolation? Mask, gloves, gown since they are in isolation in their room?

Date: 10/13/20

EPIC TEAM RESPONSE (by Buffy Lloyd-Krejci):

Be sure to follow your current policy for residents who are quarantined with unknown status. For example, are they allowed to go outside for fresh air? No need to wear gowns, gloves. Only a face mask, conduct hand hygiene and remain socially distanced. It is imperative that the resident agreed to keep the mask on at all times. If they are unable to do so then I would delay the visit until they are cleared.

Is there any guidance regarding COVID-recovered HCP?

Date: 10/13/20

EPIC TEAM RESPONSE (by Buffy Lloyd-Krejci):

Healthcare workers are not restricted to working with residents based on their “recovered” COVID-19 status. They must following the symptom based strategies for returning to work.

There is no recommendation to re-test or self-quarantine after another exposure if it’s within 90 days of their positive COVID test. If a person is symptomatic or have worsening symptoms within the 90 days, the guidance state to be re-evaluated. See below for specific details.

Data to date show that a person who has had and recovered from COVID-19 may have low levels of virus in their bodies for up to 3 months after diagnosis. This means that if the person who has recovered from COVID-19 is retested within 3 months of initial infection, they may continue to have a positive test result, even though they are not spreading COVID-19.

CDC Return-to-Work:

Symptom-based strategy for determining when HCP can return to work.

HCP with mild to moderate illness who are not severely immunocompromised:

  • At least 10 days have passed since symptoms first appeared and
  • At least 24 hours have passed since last fever without the use of fever-reducing medications and
  • Symptoms (e.g., cough, shortness of breath) have improved

Note: HCP who are not severely immunocompromised and were asymptomatic throughout their infection may return to work when at least 10 days have passed since the date of their first positive viral diagnostic test.

HCP with severe to critical illness or who are severely immunocompromised1:

  • At least 10 days and up to 20 days have passed since symptoms first appeared
  • At least 24 hours have passed since last fever without the use of fever-reducing medications and
  • Symptoms (e.g., cough, shortness of breath) have improved
  • Consider consultation with infection control experts

Return to Work Practices and Work Restrictions

After returning to work, HCP should:

  • Wear a facemask for source control at all times while in the healthcare facility until all symptoms are completely resolved or at baseline. A facemask instead of a cloth face covering should be used by these HCP for source control during this time period while in the facility. After this time period, these HCP should revert to their facility policy regarding universal source control during the pandemic.
    • A facemask for source control does not replace the need to wear an N95 or equivalent or higher-level respirator (or other recommended PPE) when indicated, including when caring for patients with suspected or confirmed SARS-CoV-2 infection.
  • Self-monitor for symptoms and seek re-evaluation from occupational health if symptoms recur or worsen.
We would like to create negative pressure rooms within our facility. Would your industrial hygienist be able to review/explain negative pressure and what it would entail to create for patient rooms?

Date: 10/17/20

The Answer and Resources:

If ever there was a time to engage the professional services of an industrial hygienist with extensive experience in indoor environmental quality, the design and implementation of airborne infection isolation rooms (AIIR) scores quite high on the list. But, to answer your question briefly…

On the whole, buildings should be positive in pressure to the outdoors. That is to say that air should move out of the interior of a facility via open pathways, such as doors, penetrations, cracks and such. If it were the other way around (with the building under negative pressure), air would be drawn into the occupied building spaces through the attic, through walls, under doors and in extreme cases from water heater exhaust pipes, chimneys, chemical storage, biohazard storage, sewer systems and the like. There are some specialty rooms in buildings that should, however, be negative compared to the adjacent areas.

Some common examples of localized rooms that should be depressurized include kitchens, janitor closets, restrooms, biohazard storage rooms, indoor pool enclosures, etc. Negative pressure helps prevent whatever is in a room of concern from migrating out into other areas. Another type of room that can be depressurized is an isolation room, or what we call an airborne infection isolation room (AIIR).

Creating an AIIR or even an airborne infection isolation wing requires thoughtful planning and a team approach. Design and implementation requires considerations to temperature control, humidity management, security, fire life and safety plans, noise, workforce divisions, PPE, air changes per hour (ACH), negative pressure (in inches of water), air barriers, localized inlets, make up air (MUA),  and many others.

The standard operating procedures and protocols will vary based on the needs and capability of the site. CSC recommends consulting the following official documents in establishing COVID-19-specific SOPs:

How are other facilities handling the fit testing requirements? We have been getting many different styles and brands of N95s and KN95s and I am struggling with what the best way to manage fit testing is.

Date: 10/20/20


Ensure you have a written respiratory program and that every employee who will wear a respirator has a medical release and a current fit test for every respirator they may wear at your facility. Look to third-party or environmental health and safety (EH&S) professionals for guidance in achieving these 3 goals. (EPIC Consultant Derrick A. Denis and his company Clark Seif Clark, Inc., represent such an environmental health and safety firm. Derrick can be reached at or 480-460-8334. ) The costs for this service vary. Fit testing one person is more expensive per person than fit testing ten people and it is more expensive on site. You want to fit test each employee with each type of N-95 you expect to have in your arsenal. If you don’t do so, OSHA may cite. They are already doing so. If staff do not pass the initial fit test, you (or your environmental health company) should work with them to adjust the device. If they still cannot pass the fit test, an alternate respirator can be selected. Employers must provide this, even if it takes an upgrade to a half-face, full face or other. The only other option is to have the employee work in a setting where respirators are not required.

Additional Information and Resources:

  1. Compliance with OSHA Respiratory Protection Standard 29 CFR § 1910.134 is a mandate and is important to ensure the health and safety of your team. Compliance will also limit liability and prevent regulatory citations, which are commonly enforced.
  2. What if I have multiple brands or models of respirators?
    Get everyone fitted with each of the potential respirator brands you might have in your arsenal.  The fit test form can then list each of the respirators that each employee is “fitted” to wear. This will prevent citations.
  3. What about my KN95s?
    You must fit test with the N95 because it is required by the OSHA Respiratory Protection Standard 29 CFR § 1910.134. You should fit test the KN95, because it is a best practice. Do not use KN95 masks when N95 respirators are required. Of course, if KN95s are all you can get due to supply chain interruptions, then you do what you must, but you do so at the peril of noncompliance and a reduced protection to your team. We are all keenly aware of the challenges skilled nursing facilities currently face with supply chain interruptions at this time. These interruptions should also be carefully documented.
  4. Can I reuse my N95s?
    Do not reuse disposable N95 respirators, unless your supply chain is interrupted, and we do recognize that this is the case for many skilled nursing facilities. There are guides for disinfection of disposable respirators, but it is best to avoid the need for such measures.
  5. How do I approach compliance with respiratory protection standards?
    There are many ways to approach getting compliance with federal respiratory protection standards 1910.134. These are noted in the next item (#6).
  6. If you are not already set up to handle this internally through your environmental health and safety  (EH&S) department, you will want to retain an outside industrial hygiene firm or another third-party environmental health and safety vendor to provide some or all of the following services:
    1. You must have a written Respiratory Protection Program (RPP) that describes how you will handle respirators at your facility.
      1. Assistance with creating this plan can include:
        1. Composition of an RPP with a little facility-specific help from your team. members, who would provide all the site and company-specific information as a collaboration.
        2. Service as an advisor to your in-house RPP developer in a collaborative effort.
        3. Assistance in peer review of your in-house produced RPP.
    2. All employees who are required to wear a respirator must have a fit test to show the device is offering adequate protection and ensuring employees understand the limitations and hazards of respirators. Fit tests are is good for one year from the date of the test. The fit test must be performed on each type of respirator an employee may wear.
      1. Assistance with fit testing can include:
        1. Environmental health and safety firm conducting fit testing at their site (usually a one-hour group class and 10-15 minutes to fit test each employee).
        2. Environmental health and safety firm conducting fit testing conducted at your facility (usually a one-hour group class and 10-15 minutes to fit test each employee).
        3. Environmental health and safety firm can conduct a train-the-trainer fit testing class for your in-house EH&S team, so they can then confidently conduct in-house fit tests on demand. (Usually a half-day class includes fit testing theory, practical matters and hands-on training.)
    3. All employees who are required to wear a respirator must have a medical evaluation. This is a one-time requirement, but most firms have the medical examination repeated annually as part of their RPP, since people change (weight gain/loss, health degradation, etc.).
      1. Assistance with medical evaluations fit testing can include:
        1. Environmental health and safety firm can conduct individual or group assistance with filling out the OSHA medical questionnaire either at our office or at your site, which usually takes one hour regardless of the size of the audience.
        2. Environmental health and safety firm can assess medical evaluations, since these documents must be reviewed and approved (or not) by a physician or other licensed health care professional.
        3. Your in-house medical professional with appropriate credentials can assess medical evaluations, since these documents must be reviewed and approved (or not) by a physician or other licensed health care professional.

EPIC recommendation for an environmental health and safety/industrial hygiene firm to serve as a third party:

Derrick A. Denis CIAQP, CAC, CIEC
Vice President of Indoor Environmental Quality, Clark Seif Clark, Inc. (CSC)
Work: 480-460-8334  |  Mobile: 602-757-8907