TB Infection Control

Window sizes and locations need to be established based upon environmental conditions at YOUR location. Select window locations that provide cross ventilation and a maximum of air changes and air dilution. Most importantly windows need to be kept OPEN.

I don't know of any portable HEPA filter units that work for the volume of a room.

Greetings!

In addition to Tariq's comments, I'd like to add that some folks use a rule-of-thumb that the openings (on opposite sides of the room) should be at least 10% of the square of the room. There are other rules of thumb based on the length vs. height of the room. There are also ways to optimize based on local climate. So, there are some design issues that could possible take up pages!!! On source for info is the WHO 2009 Natural Ventilation Guide for Healthcare Settings (That may not be the proper name; however, it's close!). I will send the link tomorrow.

As far as room air cleaners (RACs) go, one must either get the Clean Air Delivery Rate (CADR) from the manufacturer or determine it experimentally. Many room air cleaners have a very low CADR . . . Hence, you may need MANY in order to get 6-12 ACH!!! Also, because the inlet and outlet of RACs are usually relatively close to each other and generally not designed for good air mixing in a room, their actual efficiency may be lower that the calculated ACH (based on the CADR). RACs are NOT needed if you have well-designed natural ...

Greetings!

In addition to Tariq's comments, I'd like to add that some folks use a rule-of-thumb that the openings (on opposite sides of the room) should be at least 10% of the square of the room. There are other rules of thumb based on the length vs. height of the room. There are also ways to optimize based on local climate. So, there are some design issues that could possible take up pages!!! On source for info is the WHO 2009 Natural Ventilation Guide for Healthcare Settings (That may not be the proper name; however, it's close!). I will send the link tomorrow.

As far as room air cleaners (RACs) go, one must either get the Clean Air Delivery Rate (CADR) from the manufacturer or determine it experimentally. Many room air cleaners have a very low CADR . . . Hence, you may need MANY in order to get 6-12 ACH!!! Also, because the inlet and outlet of RACs are usually relatively close to each other and generally not designed for good air mixing in a room, their actual efficiency may be lower that the calculated ACH (based on the CADR). RACs are NOT needed if you have well-designed natural ventilation.

Finally, the upper-room UVGI specifications. This would also require many pages of text, and like Tariq mentioned for natural ventilation, requires some design work. Design/selection criteria include ceiling height, area of the room, type of fixture selected, UVGI output of the UVGI fixtures, humidity, reflectance, etc. The goal is to have relatively high and uniform UVGI in the upper room for maximum killing dose and relatively low UVGI in the occupied space to avoid adverse health effects (dose <= 6 mJ/cm2 (6 000 uJ/cm2). I will have to check; however, I believe the ASHRAE papers by First et al., the MRC/CSIR UVGI document for SA, and the CDC/NIOSH have been previously cited and added to references.

Hope this helps!



Regards,

Paul J

--------------------------
Sent from my BlackBerry . . . Please excuse my fumbling thumbs!

Good Morning
could i ask you to send me the link as I've not seen this info WHO 2009
Natural Ventilation Guide
Thanks

Kind Regards,

Robert Spiteri
Ozone Purification Technology
Aerobiological Tech-Eng
Cell: 082 400 9291
Tell: 011 462 5525
Fax: 086 607 6638
www.uvozone.co.za

Amal Salah Elden.

The volume of the room plays an important part in the air flow rate and
window opening size.

The bigger the volume, the bigger opening windows are required.

The tendency with natural ventilation designers are to create large
wards with large volumes by not using ceilings and using higher walls
than normal. This means that a higher natural air flow rate is required
to obtain the required ACH. The walls are raised to provide for
additional air movement to compliment that of the windows. The designs
are also mostly based on single loaded passages.

This type of design is not suitable for 99% of existing buildings and
all the new "experimental" natural ventilation ward designs available,
are based on single wards with toilet facilities. To build single ward
facilities in developing and under developed countries will simply be to
expensive.

To me it also raises the question that if a patient under treatment is
separately housed in a single ward with its own toilet facility, nursed
by HCW's and and other personnel wearing respirators, is this elaborate
design required ?

Will a single ward for this purpose, with a normal ceiling height and
cross ventilation by window ...

Amal Salah Elden.

The volume of the room plays an important part in the air flow rate and
window opening size.

The bigger the volume, the bigger opening windows are required.

The tendency with natural ventilation designers are to create large
wards with large volumes by not using ceilings and using higher walls
than normal. This means that a higher natural air flow rate is required
to obtain the required ACH. The walls are raised to provide for
additional air movement to compliment that of the windows. The designs
are also mostly based on single loaded passages.

This type of design is not suitable for 99% of existing buildings and
all the new "experimental" natural ventilation ward designs available,
are based on single wards with toilet facilities. To build single ward
facilities in developing and under developed countries will simply be to
expensive.

To me it also raises the question that if a patient under treatment is
separately housed in a single ward with its own toilet facility, nursed
by HCW's and and other personnel wearing respirators, is this elaborate
design required ?

Will a single ward for this purpose, with a normal ceiling height and
cross ventilation by window openings as required for the environmental
conditions, not be more practical to use, especially if an existing
building needs to be modified. The smaller volume will require a lower
natural air flow rate to obtain the required ACH.

Natural ventilation is also very unpredictable and wind directions can
change in seconds. The WHO states in the latest guidelines, that at its
best natural ventilation could only be relied on for 50% of the time. I
had several discussions with designers of natural ventilation wards and
the practical tests they did was only for relative short periods and
mostly at times when the wind condition suited the design. Their
conclusions were based on computer design programs. I read articles
where designers claim 12 ACH and more for natural ventilation, but it is
never stated for how long what on site test method was used and for how
long.

The best design would be to use natural ventilation combined with UVGI
or forced ventilation to ensure a continues ACH rate.

If RAC's are used the air movement could be improved with the use of
ceiling fans.

Portable HEPA filters tend to "short circuit" the filtered air flow and
has a low efficacy as far as air flow is concerned.

Dries Meyer,
Independent Consultant.

In my opinion the best option is in a single occupancy room with an independent toilet, serviceable from a single loaded corridor.
The room should have a low volume and open windows on opposite sides. Perhaps a window and louvered doors/ ventilator above the door. Fly screens are a must but will cut the air flow by a substantial amount. ( Some times over 50%)

"Natural ventilation for infection control in health-care settings" (WHO guideline 2009) may be found at the following link:

http://www.who.int/water_sanitation_health/publications/natural_ventilation/e...


 
Regards,
 
Paul J

Thank you Tark & Paul for your support and valuable discussion

i would like to agree in the ideal world a single room per person.

Come to Africa where you could have 80 + in one room and the beds are so
close that you cannot walk between the beds,a window so small that it is no
bigger than that of a single
toilet and some strange exhaust arrangement to take air out of the building
that is so suspect.

Many Windows here in Africa havesSecurity bars and sealed closed for
security reasons

There is a place in Africa where the patients are HIV + MDRTB and this is
the environment they have been living in.

Have you ever sat in a room with 6ACH at night +15 Deg C- its not pleasant,
now with 12ACH you can not heat the room

Most Patients only have one blanket and sleep fully clothed in winter.


In the morning when its at its coldest between 4.30 - 6.30 am the chill
factor outside is +7 Deg C the patients huddle together to keep warm.

The cost of heating is not an issue in some places in the world, but in
Africa it is.

Here in Africa infection control is a word that can ...

i would like to agree in the ideal world a single room per person.

Come to Africa where you could have 80 + in one room and the beds are so
close that you cannot walk between the beds,a window so small that it is no
bigger than that of a single
toilet and some strange exhaust arrangement to take air out of the building
that is so suspect.

Many Windows here in Africa havesSecurity bars and sealed closed for
security reasons

There is a place in Africa where the patients are HIV + MDRTB and this is
the environment they have been living in.

Have you ever sat in a room with 6ACH at night +15 Deg C- its not pleasant,
now with 12ACH you can not heat the room

Most Patients only have one blanket and sleep fully clothed in winter.


In the morning when its at its coldest between 4.30 - 6.30 am the chill
factor outside is +7 Deg C the patients huddle together to keep warm.

The cost of heating is not an issue in some places in the world, but in
Africa it is.

Here in Africa infection control is a word that can be spelt but not
practiced due to lack of trained staff.
The Lack of availability of N95 Masks(due to cost cutting), and the fact
that Nurses seem to think a mask can be worn more than once ( i Give away
masks to my clinics all the time) have put the nurses at risk. No amount of
UVGI or increased airflows will help them.

Shortage of soap in toilets, dirty buildings that have not seen a cleaner
for days and table tops not being cleaned and sanitised also add up to the
risk factor.

There are clinics that have the financial resources but they are ill
informed(lack of trained staff) thinking that air conditioning can be used
to control pathogens in the air and that they dont require to open windows.
When the ultraviolet is installed , assume in the summer, the air
conditioning is blowing downwards. When the season changes the staff members
change the angle of the louvers and blow air straight across the ceiling and
this in turn can affect the ultraviolet efficacy.

What is the answer ??????????????????????????????

In one hospital due to cost saving, they are removing all the UVGI units but
not increasing air into the hospital.


Reference for further reading: Effect of Turbulence on Ultraviolet
Germicidal Irradiation by David Chang and Carl Young


Kind Regards
Rob

Just a few comments in response to Dries:

1) If patients are quickly diagnosed and placed on EFFECTIVE therapy (based on knowldege of drug resistance), infectivity drops very rapidly and separation need not be long, greatly reducing the demand on isolation rooms. Remember that in many parts of the world TB, even MDR TB, is treated entirely in the community. However, rapid, specific diagnosis of TB and drug resistance is not yet widely available through Gene Xpert, and other methods, so separation, and exposure reduction may be needed because patients may not be on EFFECTIVE therapy and may remain infectious. This is especially true for re-treatment cases and those who could have highly resistant TB, such as XDR-TB.

2) The challenges to engineering controls are very different in urban and rural settings, where space is often available to spread out. IF space is available, we have seen a number of inexpensive designs for single occupancy structures that use natural ventilation, but do not depend entirely on good directional air movement because physical separation is doing much of the job of preventing transmission. True, health care workers usually must enter the room and need to be protected. Natural ventilation combined with ...

Just a few comments in response to Dries:

1) If patients are quickly diagnosed and placed on EFFECTIVE therapy (based on knowldege of drug resistance), infectivity drops very rapidly and separation need not be long, greatly reducing the demand on isolation rooms. Remember that in many parts of the world TB, even MDR TB, is treated entirely in the community. However, rapid, specific diagnosis of TB and drug resistance is not yet widely available through Gene Xpert, and other methods, so separation, and exposure reduction may be needed because patients may not be on EFFECTIVE therapy and may remain infectious. This is especially true for re-treatment cases and those who could have highly resistant TB, such as XDR-TB.

2) The challenges to engineering controls are very different in urban and rural settings, where space is often available to spread out. IF space is available, we have seen a number of inexpensive designs for single occupancy structures that use natural ventilation, but do not depend entirely on good directional air movement because physical separation is doing much of the job of preventing transmission. True, health care workers usually must enter the room and need to be protected. Natural ventilation combined with a well-fitted respirator should be sufficient since most patients are on treatment, unless at risk for highly drug resistant TB, as noted above.

3) In urban areas the challenge is greater since individual structures are not possible. All the issues around interior room volume and window size come into play, and Dries' concerns about the reliability of natural ventilation are very real, especially at night in areas where the temperature drops and windows are often closed. Administrative measures can deal with these issues to some extent, but where possible, as Dries suggests, upper room UVGI-air mixing systems (upper room UV and an ceiling mixing fan) are a very good complement to natural ventilation - in theory. Actually remembering to use the upper room UVGI-air mixing system during times natural ventilation is unlikely to be effective would require really good administrative practices. Mostly buildings tend to use one or the other, despite the potential for complementary use.

4) We have not emphasized as much as we should the importance of using a slow paddle fan with upper room UVGI - see the extensive discussion on this on GHDonline several weeks ago.

Ed

Dear All, Sounds like Robert Spiteri has summarised the issues dealing with TB in African HCFs. I have just got back from a wonderfully exciting Infection Control Africa Network meeting in Namibia and we had all sorts of interesting topics including of course TB. There were some quite interesting solutions presented.
Thanks
S

Prof Shaheen Mehtar
MBBS, FRC Path (UK), FCPath (Micro) (SA), MD (Lon)
Head of Academic Unit for Infection Prevention and Control
Tygerberg Hospital &Fac of Health Sciences, Stellenbosch Uni
PO Box 19063,
Tygerberg 7505, Cape Town
Tel: +27 21 938 5051
Fax: + 27 21 938 5065
Mobile: +27 82 852 3697
http://www.sun.ac.za/uipc
Visit the IPCAN website on
http://www.ipcan.co.za

I am sorry I was away and have just joined. I would like to reply to Tariq with some of the realities. Where one has a case or two of TB a month, or even a year, that is really no problem- we admit 7 to 15 new cases a day and at any one time have between 10 to 20 diagnosed cases of TB at TBH. The hospital was built a while back and like the hospitals in other parts of the world, do not have en-suite facilities and often in Africa, no assisted ventilation. It is a really interesting situation and the IPC practitioners must put all their skills, knowledge and experience to at least reduce if not eliminate transfer of TB- believe me it is not easy but is "do-able"- one needs are really dedicated team to make sure things happen.

Prof Shaheen Mehtar
MBBS, FRC Path (UK), FCPath (Micro) (SA), MD (Lon)
Head of Academic Unit for Infection Prevention and Control
Tygerberg Hospital &Fac of Health Sciences, Stellenbosch Uni
PO Box 19063,
Tygerberg 7505, Cape Town
Tel: +27 21 938 5051
Fax: + 27 21 938 5065
Mobile: +27 82 852 3697
http://www.sun.ac.za ...

I am sorry I was away and have just joined. I would like to reply to Tariq with some of the realities. Where one has a case or two of TB a month, or even a year, that is really no problem- we admit 7 to 15 new cases a day and at any one time have between 10 to 20 diagnosed cases of TB at TBH. The hospital was built a while back and like the hospitals in other parts of the world, do not have en-suite facilities and often in Africa, no assisted ventilation. It is a really interesting situation and the IPC practitioners must put all their skills, knowledge and experience to at least reduce if not eliminate transfer of TB- believe me it is not easy but is "do-able"- one needs are really dedicated team to make sure things happen.

Prof Shaheen Mehtar
MBBS, FRC Path (UK), FCPath (Micro) (SA), MD (Lon)
Head of Academic Unit for Infection Prevention and Control
Tygerberg Hospital &Fac of Health Sciences, Stellenbosch Uni
PO Box 19063,
Tygerberg 7505, Cape Town
Tel: +27 21 938 5051
Fax: + 27 21 938 5065
Mobile: +27 82 852 3697
http://www.sun.ac.za/uipc
Visit the IPCAN website on
http://www.ipcan.co.za

IT IS A GOOD DOCUMENT.

Prof Shaheen Mehtar
MBBS, FRC Path (UK), FCPath (Micro) (SA), MD (Lon)
Head of Academic Unit for Infection Prevention and Control
Tygerberg Hospital &Fac of Health Sciences, Stellenbosch Uni
PO Box 19063,
Tygerberg 7505, Cape Town
Tel: +27 21 938 5051
Fax: + 27 21 938 5065
Mobile: +27 82 852 3697
http://www.sun.ac.za/uipc
Visit the IPCAN website on
http://www.ipcan.co.za

Thanks Shaheen,
As an architect in Pakistan I really worry about the spaces being used to care for patients.
These discussions do speak the case for home based care. Home based care in poor crowded neighbourhoods also raises worry some questions.
There is also the question when a patient on treatment will stop passing on TB. ( Reference Dr ED Nardell)
The diseases are multiple, and the solutions need to be adaptive to local contexts.
However I do believe strongly that if we are searching for solutions then the Best practice / protocols need to be discussed first. Compromises are a fact of life. But we have to try for the best. And then for the possible.

Dear Tariq
I am from Pakistan and have been working there although I was trained and lived in England until I came to South Africa. I know exactly what you mean and I think some of the problems are quite challenging. We deal with a lot of TB in South Africa and have managed a reasonable compromise. I don't think it might be possible in Pakistan since the bed occupancy is 150% and there are people lying all over the place. In Karachi it is possible to put the patients out along the veranda; at least there is some breeze and the temperature is tolerable; the last time I was there, that is what I suggested and it seemed to work (not very easy though) but is not possible in the Punjab, I'm afraid. In the camps it is even more of a problem. In the home, there is a different challenge but not that different from South Africa. My Unit has a teaching programme for patients and healthcare workers in the community and it seems to work quite well (on the face of it anyway) but we have not been able to analyse the cross infection- hopefully ...

Dear Tariq
I am from Pakistan and have been working there although I was trained and lived in England until I came to South Africa. I know exactly what you mean and I think some of the problems are quite challenging. We deal with a lot of TB in South Africa and have managed a reasonable compromise. I don't think it might be possible in Pakistan since the bed occupancy is 150% and there are people lying all over the place. In Karachi it is possible to put the patients out along the veranda; at least there is some breeze and the temperature is tolerable; the last time I was there, that is what I suggested and it seemed to work (not very easy though) but is not possible in the Punjab, I'm afraid. In the camps it is even more of a problem. In the home, there is a different challenge but not that different from South Africa. My Unit has a teaching programme for patients and healthcare workers in the community and it seems to work quite well (on the face of it anyway) but we have not been able to analyse the cross infection- hopefully, we hope to get some funding that might allow us to evaluate this intervention. Maybe we could have a discussion which will not bore the rest of the GHDonline colleagues?
Regards
S

Prof Shaheen Mehtar
MBBS, FRC Path (UK), FCPath (Micro) (SA), MD (Lon)
Head of Academic Unit for Infection Prevention and Control
Tygerberg Hospital &Fac of Health Sciences, Stellenbosch Uni
PO Box 19063,
Tygerberg 7505, Cape Town
Tel: +27 21 938 5051
Fax: + 27 21 938 5065
Mobile: +27 82 852 3697
http://www.sun.ac.za/uipc
Visit the IPCAN website on
http://www.ipcan.co.za

Dear All
Very interesting discussions we are planning to upgrade some hospitals for MDR which is not purpose built. I will appreciate if you could guide me in this regard please find attach a drawing of a MDR ward with our plan to upgrade for infection control.

Dear all
I just come from a course on Tb infection control held in Mexico city.
Every field of IC was exposed and discussed, and health centers were
visited. I think that the intervention of Dr Paul jensen in this debate
brings enough light to us.
best regards

--
Dr M.NDIR
ConsultantTB, BP 25063 Dakar-Fann
Sénégal
cell:+221776368963

I would like to respond to several points raised by Rob Spiteri - one very genaral response on the importance of advocacy for change, and the other very specific on a citation he referred us to.

1) First, the conditions that Rob describes are truely horrific. One can speak of cost-effective interventions for poor settings but at some point you have to stop and say that conditions will not improve without the infusion of resources and that there are not good, workable solutions if resources cannot be found. Fortunately, conditions have improved in many impoverished places, but too few. Rob, I believe that advocacy for resources and change are the only solution for the conditions you describe.

2) two technical issues: disposable respirators can and should be re-used as long as they are structurally intact, ie, that a good face seal is possible. The elastic is the usual first thing to go, but molded respirators can also get crushed and loose their ability to seal.

Another technical issue is your point on UV and turbulence. You have many bigger issues in your note, but I did search out this paper and could obtain only the abstract thus far. From the abstract ...

I would like to respond to several points raised by Rob Spiteri - one very genaral response on the importance of advocacy for change, and the other very specific on a citation he referred us to.

1) First, the conditions that Rob describes are truely horrific. One can speak of cost-effective interventions for poor settings but at some point you have to stop and say that conditions will not improve without the infusion of resources and that there are not good, workable solutions if resources cannot be found. Fortunately, conditions have improved in many impoverished places, but too few. Rob, I believe that advocacy for resources and change are the only solution for the conditions you describe.

2) two technical issues: disposable respirators can and should be re-used as long as they are structurally intact, ie, that a good face seal is possible. The elastic is the usual first thing to go, but molded respirators can also get crushed and loose their ability to seal.

Another technical issue is your point on UV and turbulence. You have many bigger issues in your note, but I did search out this paper and could obtain only the abstract thus far. From the abstract I believe that this is a pure modeling paper, i.e., no experimental validation at all. I do not believe the conclusions for a minute. Study after study using room simulations have shown good air disinfection under many, many different air mixing conditions. Likewise Rod Escombe and now we have shown 73% and now 80% efficacy under real life condiditons in hospitals in Lima and South Africa respectively. We did not worry about turbulence - it does not matter! What matters is vertical air mixing and that is easily achieved with a slow paddle fan. The technology appears to be robust enough to work under many varied conditions.


Effect of Turbulence on Ultraviolet Germicidal Irradiation

by David Chang, (Consultant. E-mail: ) and Carl Young, (Vice Pres. and Dir. of Res. and Analysis, Ofc. of Global Security, Goldman, SAchs and Co., 85 Broad Street, New York, NY 10004. E-mail: )

Journal of Architectural Engineering, Vol. 13, No. 3, September 2007, pp. 152-161, (doi http://dx.doi.org/10.1061/(ASCE)1076-0431(2007)13:3(152))

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Document type: Journal Paper
Abstract: It is shown that in ultraviolet germicidal irradiation (UVGI) systems for air disinfection, where turbulence completely mixes the flow in the directions perpendicular to the net flow direction, turbulence can also act to reduce the effectiveness of the system. This occurs when the longitudinal diffusion coefficient resulting from the turbulence is large enough to reduce the effective transit time of the air through the ultraviolet irradiation zone. At the same time, depending on the radiation fluence, UV kill rate parameter, diffusion coefficient, and flow rate, the longitudinal turbulent diffusion can also increase the effectiveness of the UVGI system. The appropriate combination of parameters for ascertaining whether turbulence reduces or increases UVGI effectiveness is derived.

Dear Qaiser and Prof Shaheen
National TB Control Program is facing the challenge of implementing optimal infection control measures as part of National MDR Program. The problems are MDR wards are not purpose built ,overcrowded OPDs and limited natural ventilation of wards , climate ,untrained staff. I will appreciate if you could guide me in this regard particularly I am interested in teaching program which Prof Shaheen has mentioned.

Dear Ejaz
We too, do not have purpose built isolation facilities to the extent to which I would like, but one has to do one's best. Shall we communicate outside this forum to see what we can do? I know there is a PMIS meeting in Karachi in Dec- is that a good forum for Pakistani specialists to discuss matters of urgency?
Regards
Shaheen

Prof Shaheen Mehtar
MBBS, FRC Path (UK), FCPath (Micro) (SA), MD (Lon)
Chair of Infection Control Africa Network (ICAN)
Head of Academic Unit for Infection Prevention and Control
Tygerberg Hospital &Fac of Health Sciences, Stellenbosch Uni
PO Box 19063,
Tygerberg 7505, Cape Town
Tel: +27 21 938 5051
Fax: + 27 21 938 5065
Mobile: +27 82 852 3697
http://www.sun.ac.za/uipc
Register now for the 3rd IPCAN conference Namibia
1-3rd November, 2011
http://www.ipcan.co.za

Pakistan is an interesting situation of high MDR case rates and limited resources, generally, but much recent input of creative approaches, local philanthropy, and global fund dollars. Tariq is the architect of a remarkable new MDR ambulatory facility and laboratory in Karachi designed after attending the 2-week summer course on airborne infection control. It employes the natural breeze and shaded outdoor waiting areas that are possible in Karachi because of the climate. Perhaps Tariq would post some of these photos. Much of the funding for the Indus Hospital in Karachi comes from private philanthropy, so not everyone can do what they did. In addition, indus is treating a large population in Karachi with ambulatory MDR treatment, monitored closely by cell-phone geotracking - with outside funding I believe. Like PIH's programs in Peru and Lesotho, and others in Cambodia, the Philippines, and Ethiopia, the Indus MDR program does not depend on in-patient treatment and does not have to deal with large numbers of individual isolation rooms. There is evidence that TB patients become rapidly non-infectious on effective therapy, so I believe this is the long-term solution to the isolation problem - don't - manage most MDR patients as out-patients - except XDR TB ...

Pakistan is an interesting situation of high MDR case rates and limited resources, generally, but much recent input of creative approaches, local philanthropy, and global fund dollars. Tariq is the architect of a remarkable new MDR ambulatory facility and laboratory in Karachi designed after attending the 2-week summer course on airborne infection control. It employes the natural breeze and shaded outdoor waiting areas that are possible in Karachi because of the climate. Perhaps Tariq would post some of these photos. Much of the funding for the Indus Hospital in Karachi comes from private philanthropy, so not everyone can do what they did. In addition, indus is treating a large population in Karachi with ambulatory MDR treatment, monitored closely by cell-phone geotracking - with outside funding I believe. Like PIH's programs in Peru and Lesotho, and others in Cambodia, the Philippines, and Ethiopia, the Indus MDR program does not depend on in-patient treatment and does not have to deal with large numbers of individual isolation rooms. There is evidence that TB patients become rapidly non-infectious on effective therapy, so I believe this is the long-term solution to the isolation problem - don't - manage most MDR patients as out-patients - except XDR TB where treatment is likely to be ineffective in stopping transmission. Those patients may require long-term isolation, although novel approaches are being studied.

Ed

Just to clarify, the paper referred to about turbulence and UV is about UV installed in ventilation ducts rather than upper-room systems. Turbulence may be an important parameter for an in-duct system, simply because you only have one shot at disinfecting the air and therefore design of the unit has to be such to maximise kill at a particular flow rate. As an upper-room system relies on circulation of the contaminated air from the occupied zone through the UV zone, it is the mixing that is important. A well designed ventilation system can achieve a good level of mixing without intervention, however as indicated by Rob Spiteri this may change with season and the reality is that there are many poorly designed mechanical and natural ventilation systems out there. As Ed states paddle fans can be a simple and an effective method of enhancing the mixing in many environments. From a fluid dynamics perspective, all room air is turbulent, and for upper room UV this may even be beneficial as turbulence promotes mixing.

Best regards

Cath

------------------------------------------------
Dr Catherine Noakes CEng, MIMechE
Reader in Infection Control Engineering
Director of Pathogen Control Engineering Institute
School of Civil Engineering
University of Leeds
Leeds ...

Just to clarify, the paper referred to about turbulence and UV is about UV installed in ventilation ducts rather than upper-room systems. Turbulence may be an important parameter for an in-duct system, simply because you only have one shot at disinfecting the air and therefore design of the unit has to be such to maximise kill at a particular flow rate. As an upper-room system relies on circulation of the contaminated air from the occupied zone through the UV zone, it is the mixing that is important. A well designed ventilation system can achieve a good level of mixing without intervention, however as indicated by Rob Spiteri this may change with season and the reality is that there are many poorly designed mechanical and natural ventilation systems out there. As Ed states paddle fans can be a simple and an effective method of enhancing the mixing in many environments. From a fluid dynamics perspective, all room air is turbulent, and for upper room UV this may even be beneficial as turbulence promotes mixing.

Best regards

Cath

------------------------------------------------
Dr Catherine Noakes CEng, MIMechE
Reader in Infection Control Engineering
Director of Pathogen Control Engineering Institute
School of Civil Engineering
University of Leeds
Leeds LS2 9JT
Tel: +44 (0) 113 343 2306
Email:
------------------------------------------------

Thanks sure we can discuss while you are in Karachi,

I am not coming I am afraid. But we shall keep in touch.
Regards
Shaheen

Prof Shaheen Mehtar
MBBS, FRC Path (UK), FCPath (Micro) (SA), MD (Lon)
Head of Academic Unit for Infection Prevention and Control
Tygerberg Hospital &Fac of Health Sciences, Stellenbosch Uni
PO Box 19063,
Tygerberg 7505, Cape Town
Tel: +27 21 938 5051
Fax: + 27 21 938 5065
Mobile: +27 82 852 3697
http://www.sun.ac.za/uipc
Visit the IPCAN website on
http://www.ipcan.co.za

Dear All,

Thank you for the insightful discussion. I fully agree with Ed. All
discussion of isolation for MDR-TB is futile in countries such as India,
where there is a huge TB burden, and the extent of burden for MDR and XDR
is not even known fully.

My organisation, Operation ASHA, is successfully carrying out treatment
of MDR TB patients in Delhi, India, and patients stay in their own homes
with their families. We are using the community DOTs centres to provide
directly observed therapy for MDR patients. Our biggest challenge has been
to ensure adherance for the 2 year long treatment, which we have overcome
by intensive and repeated counselling of patients and families, using CHWs,
who belong to the community they serve.Another challenge has been the
discrimination faced by MDR-TB patients. Family members and friends of
patients seem to believe that they will surely get infected! Once again,
education has helped greatly in de-stigmatising MDR-TB, and of course in
preventing spread. The sun and the wind have helped greatly, and weather in
India is such that we can effectively use the power of nature to dispel
/kill Mycobacteria.

Isolation is expensive, and maybe hospitals are providing it ...

Dear All,

Thank you for the insightful discussion. I fully agree with Ed. All
discussion of isolation for MDR-TB is futile in countries such as India,
where there is a huge TB burden, and the extent of burden for MDR and XDR
is not even known fully.

My organisation, Operation ASHA, is successfully carrying out treatment
of MDR TB patients in Delhi, India, and patients stay in their own homes
with their families. We are using the community DOTs centres to provide
directly observed therapy for MDR patients. Our biggest challenge has been
to ensure adherance for the 2 year long treatment, which we have overcome
by intensive and repeated counselling of patients and families, using CHWs,
who belong to the community they serve.Another challenge has been the
discrimination faced by MDR-TB patients. Family members and friends of
patients seem to believe that they will surely get infected! Once again,
education has helped greatly in de-stigmatising MDR-TB, and of course in
preventing spread. The sun and the wind have helped greatly, and weather in
India is such that we can effectively use the power of nature to dispel
/kill Mycobacteria.

Isolation is expensive, and maybe hospitals are providing it, but I am
working at grassroot level, providing a very low cost, fully self-
sustaining, scalable and replicable model for TB treatment, now using
e-DOTS ( the biometric intervention devised jointly by Microsoft Research
and IIH and OpASHA) to ensure adherance. With limited resources and
seemingly unlimited work, this seems to be the only way ahead.

Yours truly,

Shelly Batra, MD

--
*Shelly Batra, MD
*
President*

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In response to UV installed in ventilation ducts, if UV is installed in an
HVAC system, the air velocity is generally constant. A well designed system
would be lamps that are placed through the middle of the air stream. This is
based on the knowledge of the lamp's behaviour knowing that the intensity of
the lamp will reduce by a certain percentage year by year. This ensures
longevity of the system.

Rob spiteri

A very important factor left out in previous correspondence is Dwell
Time. That is the time required to deactivate a bacteria with a specific
UVGI dose, ie the term µWs/cm².

Induct air conditioning systems must be provided with an irradiation
chamber to ensure that the air remain in the chamber for sufficient time
to allow the UVGI to deactivate the bacteria in one pass. The dwell time
will take care of the deactivation whether there is turbulence or not.

This is also applicable to upper volume UVGI where the irradiated upper
volume is the "irradiation" chamber. In this case it may require that
the bacteria pas through the irradiated volume more than once to be
deactivated because of the low UVGI dose.

It may be the ideal place if the UV-C lamps are placed in the centre of
an air stream, but keeping in mind that this is the part of the "duct"
with the highest airflow because there is no friction, The number of
UV-C lamps required may affect the airflow in high velocity systems.
Every installation must therefore be designed to suit the specific
application.

Dries Meyer.

Thanks Dries.
The information that you would require to place UV in a duct:

- understanding the lamp, that only 1/3rd of the lamp's total wattage is UVC
- the tables that are available on the internet by Kolwasky hold good for
induct sanitation of Air Con
- if you want to go the long method, UV Exposure Dose (Fluence) Microbes
exposed to UV irradiation are subject to an exposure dose (Fluence) that is
a function of the irradiance multiplied by the exposure time, as follows:

D = Et • IR

where
D=UV exposure dose (fluence), J/m2
Et=exposure time, sec
IR= Irradiance, W/m2

Secondly, the tables must be found for the micro organisms you wish to
control. These tables are also found on the internet or in Kolwasky's books

Rob

I would like to cut off further discussion of UV in ducts as not entirely appropriate for this group. First, many of the readers are working in areas without mechanical ventilation systems. Secondly, it is of little comfort to know that only when the air leaves the room is it disinfected by the UV in the ductwork. What is usually needed is air disinfection in the room occupied by the infectious source and workers or other patients. For that we need upper room UVGI-air mixing systems. Air cleaning machines are also used, but most often do not move enough air to be very useful.

This detail on duct UV is probably not of great interest to our readership.

Ed Nardell, MD, moderator

How does one assess the UVGI fixture assuming a salesman has arrived at your
doorstep and offered you the equipment?

TYPE OF EQUIPMENT OFFERED

A
B
C

Round
Rectangular
Round

9W UVC Lamp
36W UVC Lamp
2 x 18W UVC Lamps
1 Fan facing downwards 123cm/H 1 Fan
downward facing with grill 37cm/H 2 Fans 80cm/H
facing outwards no grill
UV Fixture 5 Louvers
UV Fixture 5 Louvers
Optional - No Louvers


3, 5 or 9 Louvers
Mercury content set by Manufacturer Mercury
content set by Manufacturer Mercury content
set by Manufacturer
No additional features
Additional features - Titanium dioxide

Ionizer
Ease of maintenance - can only be carried Can be
maintained by medical engineering crew Can be maintained by
medical engineering crew
out by a fully skilled member of manufacturer
staff
No training given to hospital engineering staff No training
given to hospital engineering staff Training given to
hospital engineering staff
on maintenance
on maintenance
Installation as per National Institute of Electrical Installation
as per National Institute of Electrical Installation as per
National Institute of Electrical
Engineers
Engineers
Engineers/ Clinical & Hospital Engineers

All three comply to eye safety

Reliability:

Early lamp failure - Possible 5% Early
lamp failure - 1%
Early ...

How does one assess the UVGI fixture assuming a salesman has arrived at your
doorstep and offered you the equipment?

TYPE OF EQUIPMENT OFFERED

A
B
C

Round
Rectangular
Round

9W UVC Lamp
36W UVC Lamp
2 x 18W UVC Lamps
1 Fan facing downwards 123cm/H 1 Fan
downward facing with grill 37cm/H 2 Fans 80cm/H
facing outwards no grill
UV Fixture 5 Louvers
UV Fixture 5 Louvers
Optional - No Louvers


3, 5 or 9 Louvers
Mercury content set by Manufacturer Mercury
content set by Manufacturer Mercury content
set by Manufacturer
No additional features
Additional features - Titanium dioxide

Ionizer
Ease of maintenance - can only be carried Can be
maintained by medical engineering crew Can be maintained by
medical engineering crew
out by a fully skilled member of manufacturer
staff
No training given to hospital engineering staff No training
given to hospital engineering staff Training given to
hospital engineering staff
on maintenance
on maintenance
Installation as per National Institute of Electrical Installation
as per National Institute of Electrical Installation as per
National Institute of Electrical
Engineers
Engineers
Engineers/ Clinical & Hospital Engineers

All three comply to eye safety

Reliability:

Early lamp failure - Possible 5% Early
lamp failure - 1%
Early lamp failure - 1%

Longevity:
Lamp replacement every 12 Months Lamp
replacement every 2 years Lamp
replacement every 2 years. With monitoring,


lamp can be replaced every 2.5 years
Performance:
40% lamp efficiency lost in first year 12%
lamp efficiency lost in first year 12% lamp
efficiency lost in first year
Lamp lasts a maximum of 18 months Lamp lasts a
good 2 years Lamp lasts a
good 2 - 2.5 years

The UV industry in the medical field is the only field that I have ever
worked in that is impossible to validate the equipment once it is installed
for the purpose that it is intended.

Unlike the food industry, you have a set of objectives and criteria to meet.
The whole system is governed by how much money they can save when installing
a system. While one can validate what happens in the food industry, one
cannot do the same in the medical field.
Often, in the food industry, the installer of the equipment does not wish
his competitors to know what he has installed and for what reason as this
gives a competitive edge in the market place.
eg He may have to deliver his goods to the client once a week instead of
twice a week because he has longevity having removed the bacteria from the
goods.

The question is often asked how fast or how slow must the pedal fan be. In
my experience the pedal fan should be very slow. Chang and Young also agree
with me in their book 'Effect of Turbulence on Ultraviolet Germicidal
Irradiation'

For every UV lamp that is being removed in the hospitals in South Africa for
whatever reason, two new ones are being fitted in other parts of the
country.

Rob

Sorry guys but the information did not come out in table form as intended. I
will resend once I understand what went wrong.

Rob

Though not applicable in resource limited settings, it is actually
interesting to read what others are doing, and great to know how
engineering has the potential to dispel/destroy Mycobacteria.

--
*Shelly Batra, MD
*
President*

*This email and any attachments to it may be confidential and are intended
solely for the use of the individual to whom they are addressed. Views or
opinions expressed therein do not necessarily represent those of Operation
ASHA. If you are not the intended recipient of this email, you must
neither take any action based upon its contents, nor copy or show it to
anyone. We apologize if you have received this email in error.*
*

I agree with Ed that in duct UVGI should not form part of this
discussion and I want to add that participants should not copy parts of
handbooks directly or indirectly in the discussion.

To my mind the discussions should be based on personal experience and
knowledge.

The situation as shown in Shelly Batra's discussion can be seen as a
typical situation in under developed countries as well as in some
developing countries. The living conditions are ghastly, but because the
people have been living in those conditions for generations, it has
become an accepted standard to them because they normally have no other
option.

This is a cycle that needs to be broken, but it will not be easy.The GHD
community should also concentrate on finding affordable solutions to
assist health care workers countries who are in this position.

Because of the lack of maintenance and funds in resource limited
countries, the most economical method to be used will be the use of the
prevailing environmental conditions. This will normally be a challenge,
but the result will make it worthwhile.

Dries Meyer.

In my opinion the only way forward is to get Corporate Companies involved to sponsor the use of UVGI. The cost factor limits hospitals to realise the true potential of the technology and by installing 20 or 30 units accross a large hospital you are generating a false sense of security. In contrast if you could install 100 or 150 units it will dramatically change the outcome of the game. It is all about travel time and multiple periods of irradiation. But to have so many units in a hospital has its own problems. Upper air units will not work due to reflectivity off the walls so wall mounted units would be the way to go. They are safe and the irridiation is done in a closed environment (enclosure or box). The cost of such a roll-out is still the prohibiting factor and if corporate companies are asked to sponsor such units they will require some sort of possitive PR in return. Possibly this could be linked to the CSI of such corporates???

Still on the topic of costs, as far as I am concerned the cost of the technology is its own limiting factor. UVC and UVGI manufacturers have to design and manufacture their devices with the cost of production and a possible sales profit in mind. They only have one opportunity to sell the unit and make a sale profit, and at the end of the day it is still a business that needs to pay salaries etc. The cost of production may interfere with optimal functionality and effectiveness of the unit. Surely if you take a normal wall mounted unit with fans on each side to induce flow communication between the air and the lamps and you install 4 x 15W UVC lamps in it, surely that will render better results than a small unit with a 9w lamp. The travel time may be short in closed wall mounted units but if you add stronger lamps and have reflectivity inside the unit you can increase the starting UVC lamp power to almost double, although the reflectivity is achieved by means of alluminium which is costly. The wall mounted units are closed units so General Health & Safety standards will not be ...

Still on the topic of costs, as far as I am concerned the cost of the technology is its own limiting factor. UVC and UVGI manufacturers have to design and manufacture their devices with the cost of production and a possible sales profit in mind. They only have one opportunity to sell the unit and make a sale profit, and at the end of the day it is still a business that needs to pay salaries etc. The cost of production may interfere with optimal functionality and effectiveness of the unit. Surely if you take a normal wall mounted unit with fans on each side to induce flow communication between the air and the lamps and you install 4 x 15W UVC lamps in it, surely that will render better results than a small unit with a 9w lamp. The travel time may be short in closed wall mounted units but if you add stronger lamps and have reflectivity inside the unit you can increase the starting UVC lamp power to almost double, although the reflectivity is achieved by means of alluminium which is costly. The wall mounted units are closed units so General Health & Safety standards will not be a problem vs. the potential eye and skin problems with upper air units. If multiple units are placed in the same room or corridor you will have multiple pass cycles through the fans of each unit. But bigger units mean bigger costs and more expensive maintenance in replacing the lamps regularly. Surely governments can give some kind of reward to companies that would be willing to sposor such units?
I was told that all the UVC and UVGI procurement of the South African Government and Department of Health has been stopped due to the massive maintenance costs and that the NIOH was tasked with testing the technology and setting up a universal standard for UVC in South Africa. Although I fully support this action, government is suggesting that the new UVC standard be rolled out to all hospitals as a compulsary tool - I wonder how a government in a economic dip is going to find funds to enforce this without the help of the private sector? What are your thoughts on this matter and should corporate companies that sponsor this initiaitive be rewarded and if so, how?

More responses to your UVGI questions.
On Feb 16, 2012, at 10:02 AM, GHDonline (Hennie Mostert) wrote:

Hennie Mostert replied to the discussion "Engineering control" in the TB Infection Control community.

Reply contents:
"Still on the topic of costs, as far as I am concerned the cost of the technology is its own limiting factor. UVC and UVGI manufacturers have to design and manufacture their devices with the cost of production and a possible sales profit in mind. They only have one opportunity to sell the unit and make a sale profit, and at the end of the day it is still a business that needs to pay salaries etc. The cost of production may interfere with optimal functionality and effectiveness of the unit.
EN: We are working to produce a standard international UV fixture design that would be inexpensive and reliable. We are not there yet, but working on it in collaboration with UP and researchers at Harvard.



Surely if you take a normal wall mounted unit with fans on each side to induce flow communication between the air and the lamps and you install 4 x 15W UVC lamps in it, surely that will render better results ...

More responses to your UVGI questions.
On Feb 16, 2012, at 10:02 AM, GHDonline (Hennie Mostert) wrote:

Hennie Mostert replied to the discussion "Engineering control" in the TB Infection Control community.

Reply contents:
"Still on the topic of costs, as far as I am concerned the cost of the technology is its own limiting factor. UVC and UVGI manufacturers have to design and manufacture their devices with the cost of production and a possible sales profit in mind. They only have one opportunity to sell the unit and make a sale profit, and at the end of the day it is still a business that needs to pay salaries etc. The cost of production may interfere with optimal functionality and effectiveness of the unit.
EN: We are working to produce a standard international UV fixture design that would be inexpensive and reliable. We are not there yet, but working on it in collaboration with UP and researchers at Harvard.



Surely if you take a normal wall mounted unit with fans on each side to induce flow communication between the air and the lamps and you install 4 x 15W UVC lamps in it, surely that will render better results than a small unit with a 9w lamp. The travel time may be short in closed wall mounted units but if you add stronger lamps and have reflectivity inside the unit you can increase the starting UVC lamp power to almost double, although the reflectivity is achieved by means of alluminium which is costly. The wall mounted units are closed units so General Health & Safety standards will not be a problem vs. the potential eye and skin problems with upper air units. If multiple units are placed in the same room or corridor you will have multiple pass cycles through the fans of each unit. But bigger units mean bigger costs and more expensive maintenance in replacing the lamps regularly. Surely governments can give some kind of reward to companies that would be willing to sposor such units?

EN: this is too much detail for this forum, but I want to state clearly that using UV in a box with fans is a major error in the application of UVGI simply because you cannot produce 10-20 equivalent room air changes per hour - and that is needed. Upper room UVGI fixtures do this with paddle fans to assure air mixing


I was told that all the UVC and UVGI procurement of the South African Government and Department of Health has been stopped due to the massive maintenance costs and that the NIOH was tasked with testing the technology and setting up a universal standard for UVC in South Africa. Although I fully support this action, government is suggesting that the new UVC standard be rolled out to all hospitals as a compulsary tool - I wonder how a government in a economic dip is going to find funds to enforce this without the help of the private sector? What are your thoughts on this matter and should corporate companies that sponsor this initiaitive be rewarded and if so, how?"

EN: to be sustainable UVGI applications cannot depend on the good will of corporations. They must be well designed an affordable, and reasonable to maintain.

MORE IMPORTANT THAN ANY AIR DISINFECTION STRATEGY, NATURAL VENTILATION, UV, ETC, IS THE ACTIVE FINDING OF INFECTIOUS CASES AND RAPID IMPLEMENTATION OF EFFECTIVE TREATMENT.

If patients are on effective treatment, transmission stops rapidly and air disinfection becomes much less important.

Ed Nardell, MD

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Edward A. Nardell, MD
Associate Professor
Harvard Medical School
Harvard School of Public Health

Brigham & Women's Hospital
Division of Global Health Equity
Partners In Health
641 Huntington Ave
3A-03
Boston, MA 02115

432-2080 (academic); 877-9412 (cell)

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The main question here is that of cost versus longevity/design.
The cost of the unit falls away within the first year. After the first year on many units, the lamps need to be replaced as their efficiency will have dropped by +/- 40%. This is true of smaller wattage lamps.
With the lamps that are +/- 18 W and above it is possible to optimise performance to give longevity to the units with extended lamp life of 2 years or more. This has been proven by many of the users by monitoring the lamps on a regular basis thus making this particular unit of UVGI cost effective. Hospitals and clinics in South Africa that have used these particular units monitor their UVGI systems using the UVC meter every 6 months. In a survey carried out by myself, all have reported back no early lamp life failure. It is important to monitor UVGI systems and take meter readings at regular intervals. This plays an important role in cost effectiveness knowing when to replace the lamps other than being told to replace the lamps every 12 months by the manufacturer.

Sponsorship and branding by companies is only but a limited success as the ...

The main question here is that of cost versus longevity/design.
The cost of the unit falls away within the first year. After the first year on many units, the lamps need to be replaced as their efficiency will have dropped by +/- 40%. This is true of smaller wattage lamps.
With the lamps that are +/- 18 W and above it is possible to optimise performance to give longevity to the units with extended lamp life of 2 years or more. This has been proven by many of the users by monitoring the lamps on a regular basis thus making this particular unit of UVGI cost effective. Hospitals and clinics in South Africa that have used these particular units monitor their UVGI systems using the UVC meter every 6 months. In a survey carried out by myself, all have reported back no early lamp life failure. It is important to monitor UVGI systems and take meter readings at regular intervals. This plays an important role in cost effectiveness knowing when to replace the lamps other than being told to replace the lamps every 12 months by the manufacturer.

Sponsorship and branding by companies is only but a limited success as the companies offering the sponsorship are limited to the amount they are permitted to spent on a single item.
As a manufacturer of UVGI units, for every 10 units I sell I sponsor 1 unit to children's homes and clinics that have limited resources. These I install free of charge and I continue to maintain the units every 2 years. This I have been doing for the past 12 years.

Kind Regards
Robert Spiteri