★ SOSA · clinics, polyclinics & medical centres
Every one of these starts the same way: which rooms are clinical, what does housekeeping already know is wrong, and what is the ceiling height
★ ★ ★ ★ ★
★★★★★
"I described the whole place — 5,000 sq ft, six departments, one waiting hall — and the answer began by taking four rooms out of scope."
Four rooms removed
★★★★★
"Cleaning smell every morning, patients had mentioned it. The fix was the mopping schedule and a window. We bought the machine afterwards, for a different reason."
Schedule, then machine
★★★★★
"Three floors and a lobby. I wanted a number and got a calculation instead, which was more useful."
A calculation
★★★★★
"Fitting out a new clinic. Being told where fragrance belongs in the sequence — after ventilation, after housekeeping — shaped the fit-out itself."
Fitted into the sequence
★★★★★
"We have patients who react to strong smells and we still wanted a decent lobby. Zoning and a low setting did both."
Both, by zoning
★★★★★
"Four polyclinics, one recognisable fragrance, and a straight answer on what it would cost per year. No claims attached."
Costed, not claimed
★★★★★
"I described the whole place — 5,000 sq ft, six departments, one waiting hall — and the answer began by taking four rooms out of scope."
Four rooms removed
★★★★★
"Cleaning smell every morning, patients had mentioned it. The fix was the mopping schedule and a window. We bought the machine afterwards, for a different reason."
Schedule, then machine
★★★★★
"Three floors and a lobby. I wanted a number and got a calculation instead, which was more useful."
A calculation
★★★★★
"Fitting out a new clinic. Being told where fragrance belongs in the sequence — after ventilation, after housekeeping — shaped the fit-out itself."
Fitted into the sequence
★★★★★
"We have patients who react to strong smells and we still wanted a decent lobby. Zoning and a low setting did both."
Both, by zoning
★★★★★
"Four polyclinics, one recognisable fragrance, and a straight answer on what it would cost per year. No claims attached."
Costed, not claimed
★ ★ SOSA Vaayu — waterless, timed, key-locked ₹11,999 SOSA Aangan — up to 3,000 m³, HVAC-ready ₹25,999
✓ No medical claims. A diffuser does not purify, disinfect or treat anything ✓ Clinical rooms stay fragrance-free · fix the source before you cover a smell ✓ Drain traps, bins and the AC drain pan first. Those three are free
Founder Diaries · Clinics & Medical Centres · Air Changes, Occupancy & the Six O'Clock Problem
The sum, worked: a 900 sq ft hall at 3.2 metres is about 268 m³. At six people, a design figure of 8 litres per second per person is 48 l/s, which is 173 m³ an hour, or 0.6 air changes. At fifty people it is 400 l/s, which is 1,440 m³ an hour, or 5.4 air changes — more than eight times the morning requirement, in a room that has not changed size.
Then the four things that changed: the entrance door that was propped at eight and shut by ten · a toilet extract wired to an occupancy-sensor light, so it runs only while somebody is in there · the fresh-air damper closed to save on cooling, or the air conditioning left on full recirculation · forty fabric seats, roughly 44 m² of soft surface against 84 m² of floor, and the only large surface in the hall nobody cleans daily.
And fragrance: it adds no air changes and removes nothing. Once the air is right, a Vaayu at ₹11,999 holds one low background through the opening hours. Housekeeping and presentation, no clinical effect, and clinical rooms stay fragrance-free.
The range · last, by choicefrom ₹899Shop → 
Vaayu · one steady level₹11,999Shop → 
The lightest scentsfrom ₹299Shop →
It is a ventilation and occupancy problem, and I can show you that with arithmetic before either of us mentions a machine. Your waiting hall has one volume all day. It does not get larger at six in the evening. What changes is the number of people standing in it, and the amount of fresh air a room needs rises with the people while the room itself stays exactly the same size. A hall that is comfortable with six people in it and unpleasant with fifty has not developed a fragrance deficiency between nine and six; it has run out of air changes, and it did so at some identifiable hour that you can find this week with a notebook and a thirty-five-hundred-rupee meter. That is good news, because it means the problem has a location and a cost rather than a mood. This page does the sum first, in full, with the numbers written out so you can substitute your own. Then it goes through the four things that are almost always different at six from how they were at nine — the entrance door, the toilet extract, the air-conditioning mode and the fabric seating. And then, at the end and only at the end, it says plainly what a fragrance can and cannot do in that hall once the air has been put right, because the honest answer to your question is that fragrance is not the correction and will not become the correction by being turned up.
Quick answers — read this first
Free, and it settles the argument in one day: count the people in the hall at nine, at two and at six, including standing attendants, and write the three numbers down · work out the hall's volume as floor area in square feet divided by 10.76, multiplied by ceiling height in metres · ask your air-conditioning contractor for one figure from the drawing — the fresh-air quantity the hall was designed for · prop the entrance door open for twenty minutes at half past five and notice what happens · hold a tissue to the toilet extract grille at nine and again at six and see whether the fan is running on both occasions.The sum, worked: a 900 sq ft hall at 3.2 metres is about 268 m³. At six people, a design figure of 8 litres per second per person is 48 l/s, which is 173 m³ an hour, or 0.6 air changes. At fifty people it is 400 l/s, which is 1,440 m³ an hour, or 5.4 air changes — more than eight times the morning requirement, in a room that has not changed size.
Then the four things that changed: the entrance door that was propped at eight and shut by ten · a toilet extract wired to an occupancy-sensor light, so it runs only while somebody is in there · the fresh-air damper closed to save on cooling, or the air conditioning left on full recirculation · forty fabric seats, roughly 44 m² of soft surface against 84 m² of floor, and the only large surface in the hall nobody cleans daily.
And fragrance: it adds no air changes and removes nothing. Once the air is right, a Vaayu at ₹11,999 holds one low background through the opening hours. Housekeeping and presentation, no clinical effect, and clinical rooms stay fragrance-free.
The short answer
Short answer: it is a ventilation and occupancy problem, and the arithmetic proves it before any product is involved. The hall has one volume all day, but the fresh air it needs scales with the number of people in it. A 900 sq ft hall at 3.2 metres is about 268 cubic metres; at six people a design figure of 8 litres per second per person asks for 173 cubic metres an hour, and at fifty people it asks for 1,440 — more than eight times as much, in a room that has not grown. Fragrance adds no air changes, so it is not the correction.
The order, and why: count the people first, because that is the variable that actually moved; then get the hall's volume from the sum; then ask your contractor for the fresh-air quantity on the drawing and compare it with the evening requirement. Only after those three numbers exist should you look at the four usual suspects — the entrance door, a toilet extract wired to a sensor light, a closed fresh-air damper or recirculating air conditioning, and fabric seating. Every item in that list is either free to check or cheap to correct, and a 3,500-rupee carbon-dioxide meter turns the whole conversation into a reading rather than an opinion.
The last line, costed: an extract run-on timer at Rs 1,500 to Rs 3,500 a fan; an extract fan replaced and interlocked at Rs 3,500 to Rs 8,000; a fresh-air damper actuator at Rs 2,500 to Rs 6,000; the air-conditioning maintenance scope widened to the drain pan, condensate trap, blower wheel and two coil cleans a year at roughly Rs 25,000 to Rs 45,000 for a ten-unit clinic; wipeable perforated seating at the next refit for about the same money as fabric. Then, optionally, the Vaayu at Rs 11,999 for public areas on one low setting. A diffuser is not an air purifier and makes no clinical claim.
In this guide
Count the people, then the room
The diagnosis · ₹0
Only after the air is right
Vaayu · ₹11,999
One admin cabin
Reeds · from ₹749
Straight answer
Our waiting area is fine at nine and unpleasant by six. Is that fragrance or ventilation, and how do we prove which?
1. It is ventilation and occupancy, and here is the proof before any product appears. Take the hall's volume: floor area in square feet divided by 10.76 gives square metres, multiplied by the ceiling height in metres gives cubic metres. A 900 square foot hall with a 3.2 metre ceiling is 83.6 square metres and therefore about 268 cubic metres. That number is the same at nine in the morning and at six in the evening. Now take the other number, the one that actually moved: the people. Count them — seated, standing and accompanying — at nine, at two and at six. In most multi-speciality clinics the morning figure is single digits and the evening figure is at or beyond the seat count, because the evening peak brings attendants who stand. Fresh-air requirement is per person. Room volume is not. That asymmetry is the whole of your problem.
2. Put your own design figure into the sum and watch the gap open. Ask your air-conditioning contractor for one number from the drawing: the fresh-air quantity the hall was designed for, and the per-person figure it was based on. If that figure is 8 litres per second per person — a common design value, and the point here is the arithmetic rather than the particular number, so substitute yours — then six people need 48 litres per second, which is 173 cubic metres an hour, which against 268 cubic metres is 0.6 air changes an hour. Fifty people need 400 litres per second, which is 1,440 cubic metres an hour, which is 5.4 air changes. That is more than eight times the morning requirement from the same fan, in the same room, with the same machine running. If the installed fresh-air supply is doing, say, 300 cubic metres an hour, it is comfortably ample at nine with 1.1 air changes and it is short by about 1,140 cubic metres an hour at six. Nothing is broken. The building is simply being asked for eight times as much as it was asked for seven hours earlier.
3. Buy one instrument and stop arguing. A hand-held carbon-dioxide meter from about ₹3,500 turns this from a discussion into a log. Carbon dioxide in an occupied room rises as air is breathed and falls as fresh air arrives, which makes a reading a proxy for air change against occupancy and nothing else — I am using it as a ventilation instrument, not as a health measure, and it should not be presented to patients or staff as anything else. Take a reading outdoors, then in the hall at nine, at two and at six, on three consecutive days. A reading that climbs through the day and does not recover overnight tells you the extract is not clearing the building; a reading that spikes with the evening queue and drops within twenty minutes of the entrance door being propped tells you exactly what the correction is and what it is worth.
4. Then find the four things that are different at six from how they were at nine. In my experience of walking Indian clinics in the evening, it is almost always some combination of these four. The entrance door was propped open at eight while housekeeping and staff came in, and it has been shut since about ten, which means the hall spent its morning on free ventilation and its evening on mechanical fresh air alone. The toilet extract is wired to the occupancy-sensor light, so it runs for three minutes when somebody is in there and never between, which is the opposite of how a sanitary extract should behave in a building that is open twelve hours. The fresh-air damper has been closed, or the air conditioning left on full recirculation, by somebody entirely reasonably chasing a cooling bill. And the seating is fabric: forty seats is roughly forty-four square metres of soft, absorbent surface against eighty-four square metres of floor, which makes it the second-largest surface in your hall and the only large one that is not cleaned daily.
5. Correct in cost order, because three of the four are free or nearly free. The damper and the air-conditioning mode are a settings change. The door is a decision and, if it has lost its closer, about ₹500. The extract is the one real repair: a run-on timer so the fan continues for fifteen minutes after the light goes off is ₹1,500 to ₹3,500 a fan, and a dead fan replaced and interlocked properly is ₹3,500 to ₹8,000. The seating is the same money at the next refit, spent on perforated or wipeable material instead of fabric. The air-conditioning maintenance scope widened to name the drain pan, the condensate trap, the blower wheel and two coil cleans a year is roughly ₹25,000 to ₹45,000 a year for a ten-unit clinic and is mostly a renegotiation of money you already spend. Where a clinic should spend first sets all of this out as a budget rather than as a checklist.
6. And here is what fragrance can and cannot do, which is the actual answer to your question. It cannot add an air change. It cannot remove what fifty people and twelve hours put into a room, it cannot change what forty fabric seats have absorbed, and it cannot make a shut building behave like one with its door open. Run over a hall that is short of air, it is a second smell added to a first, and patients notice the pair more clearly than they noticed the one. What it can do, once the air is right, is hold one low, steady, unremarkable background from opening to closing so that the hall smells of nothing in particular at nine and at six alike — and that is presentation and housekeeping, in the same category as the seating and the signage. The Vaayu at ₹11,999 does that on one setting with a key-lock so nobody turns it up at the evening peak. It is not a treatment, a diffuser is not an air purifier, and consultation rooms, procedure rooms, dressing rooms, sample collection, laboratories, dispensing, imaging, oncology day-care and paediatric clinical areas stay fragrance-free with their doors shut.
A portion of every order supports girl-child education through Nanhi Kali.
2. Put your own design figure into the sum and watch the gap open. Ask your air-conditioning contractor for one number from the drawing: the fresh-air quantity the hall was designed for, and the per-person figure it was based on. If that figure is 8 litres per second per person — a common design value, and the point here is the arithmetic rather than the particular number, so substitute yours — then six people need 48 litres per second, which is 173 cubic metres an hour, which against 268 cubic metres is 0.6 air changes an hour. Fifty people need 400 litres per second, which is 1,440 cubic metres an hour, which is 5.4 air changes. That is more than eight times the morning requirement from the same fan, in the same room, with the same machine running. If the installed fresh-air supply is doing, say, 300 cubic metres an hour, it is comfortably ample at nine with 1.1 air changes and it is short by about 1,140 cubic metres an hour at six. Nothing is broken. The building is simply being asked for eight times as much as it was asked for seven hours earlier.
3. Buy one instrument and stop arguing. A hand-held carbon-dioxide meter from about ₹3,500 turns this from a discussion into a log. Carbon dioxide in an occupied room rises as air is breathed and falls as fresh air arrives, which makes a reading a proxy for air change against occupancy and nothing else — I am using it as a ventilation instrument, not as a health measure, and it should not be presented to patients or staff as anything else. Take a reading outdoors, then in the hall at nine, at two and at six, on three consecutive days. A reading that climbs through the day and does not recover overnight tells you the extract is not clearing the building; a reading that spikes with the evening queue and drops within twenty minutes of the entrance door being propped tells you exactly what the correction is and what it is worth.
4. Then find the four things that are different at six from how they were at nine. In my experience of walking Indian clinics in the evening, it is almost always some combination of these four. The entrance door was propped open at eight while housekeeping and staff came in, and it has been shut since about ten, which means the hall spent its morning on free ventilation and its evening on mechanical fresh air alone. The toilet extract is wired to the occupancy-sensor light, so it runs for three minutes when somebody is in there and never between, which is the opposite of how a sanitary extract should behave in a building that is open twelve hours. The fresh-air damper has been closed, or the air conditioning left on full recirculation, by somebody entirely reasonably chasing a cooling bill. And the seating is fabric: forty seats is roughly forty-four square metres of soft, absorbent surface against eighty-four square metres of floor, which makes it the second-largest surface in your hall and the only large one that is not cleaned daily.
5. Correct in cost order, because three of the four are free or nearly free. The damper and the air-conditioning mode are a settings change. The door is a decision and, if it has lost its closer, about ₹500. The extract is the one real repair: a run-on timer so the fan continues for fifteen minutes after the light goes off is ₹1,500 to ₹3,500 a fan, and a dead fan replaced and interlocked properly is ₹3,500 to ₹8,000. The seating is the same money at the next refit, spent on perforated or wipeable material instead of fabric. The air-conditioning maintenance scope widened to name the drain pan, the condensate trap, the blower wheel and two coil cleans a year is roughly ₹25,000 to ₹45,000 a year for a ten-unit clinic and is mostly a renegotiation of money you already spend. Where a clinic should spend first sets all of this out as a budget rather than as a checklist.
6. And here is what fragrance can and cannot do, which is the actual answer to your question. It cannot add an air change. It cannot remove what fifty people and twelve hours put into a room, it cannot change what forty fabric seats have absorbed, and it cannot make a shut building behave like one with its door open. Run over a hall that is short of air, it is a second smell added to a first, and patients notice the pair more clearly than they noticed the one. What it can do, once the air is right, is hold one low, steady, unremarkable background from opening to closing so that the hall smells of nothing in particular at nine and at six alike — and that is presentation and housekeeping, in the same category as the seating and the signage. The Vaayu at ₹11,999 does that on one setting with a key-lock so nobody turns it up at the evening peak. It is not a treatment, a diffuser is not an air purifier, and consultation rooms, procedure rooms, dressing rooms, sample collection, laboratories, dispensing, imaging, oncology day-care and paediatric clinical areas stay fragrance-free with their doors shut.
A portion of every order supports girl-child education through Nanhi Kali.
TL;DR: ventilation and occupancy, and the sum proves it. The hall is one volume all day; the fresh air it needs scales with people. 900 sq ft at 3.2 m is 268 m³; six people at 8 l/s each need 173 m³/h, fifty need 1,440. Then check four things that changed since nine: the entrance door, a toilet extract on a sensor light, a closed damper or recirculating air conditioning, and forty fabric seats. Fragrance adds no air changes and is not the correction.
What actually changes a six o'clock waiting hall, in order
SOSA commercial scenting from ₹899
The order is by cost and by consequence rather than by how interesting each item is. Three counts and three carbon-dioxide readings are free. The fresh-air damper and the air-conditioning mode are a settings change. The entrance door is a decision and a ₹500 closer. The toilet extract is a ₹1,500 to ₹3,500 run-on timer or a ₹3,500 to ₹8,000 fan. The seating is the same money at the next refit, spent on a different material. Fragrance comes after all of them and it corrects none of them: the Vaayu is ₹11,999, the Aangan is ₹25,999 for an atrium or a whole floor, and an alcohol-free reed diffuser from ₹749 suits an administrative cabin. Free shipping above ₹499.
The two counts, and the sum that settles it
I want to put the arithmetic before the opinions, because this is one of the few questions in my trade where a notebook genuinely ends the argument in a day. There are two numbers. The first is the hall's volume, which is fixed: floor area in square feet divided by 10.76, multiplied by ceiling height in metres. The second is the number of people in it, which is not fixed and which is the only thing that materially changed between the hall you liked at nine and the hall you did not like at six. Fresh-air requirement is specified per person; room volume is not. A hall that goes from six occupants to fifty has multiplied its requirement by more than eight while keeping the same fan, the same ductwork and the same room. Once those two numbers are written down side by side, nobody in the building argues about whether this is a fragrance problem, because the gap is visible and it has units. Everything in this section is free except one instrument that costs about ₹3,500 and that I would buy for any facility running a public waiting hall, and none of it requires a contractor to be present. The morning-good, evening-stale pattern is the same question asked more generally; this page is the version with the sums in it.
1
THE TWO COUNTS AND THE INSTRUMENT
Three occupancy counts, three readings, and one figure from the drawing
Count the people at nine, at two and at six, on three consecutive working days, and count everybody: seated patients, standing patients, accompanying relatives and anybody waiting for a report. Write the nine numbers on one sheet. In most multi-speciality clinics the morning count is single digits because the first appointments are staggered and the evening count is at or beyond the seat count because the after-work peak brings an attendant with each patient. A forty-seat hall very commonly holds fifty people at six, a dozen of them standing. Then take the hall's volume. 900 square feet divided by 10.76 is 83.6 square metres; times a 3.2 metre ceiling is about 268 cubic metres. Write that next to the nine numbers. Then ask your air-conditioning contractor for one thing: the fresh-air quantity on the drawing for that hall, and the per-person figure it was designed against. Every properly drawn system has both. If you are given 8 litres per second per person, the arithmetic goes like this: 6 people × 8 = 48 l/s, and 48 × 3.6 = 173 cubic metres an hour, which against 268 cubic metres is 0.6 air changes an hour. 50 people × 8 = 400 l/s, and 400 × 3.6 = 1,440 cubic metres an hour, which is 5.4 air changes. The ratio between those two is 8.3, and it is the entire explanation of your day. Then buy the one instrument. A hand-held carbon-dioxide meter from about ₹3,500 gives you a reading that rises as the air in a room is breathed and falls as fresh air arrives, which makes it a proxy for air change against occupancy. I use it for nothing else and nor should you: it is a ventilation instrument, it is not a measure of anybody's health, and it does not belong on a notice board or in a conversation with a patient. Take an outdoor reading, then readings in the hall at your three hours for three days, and add one more — a reading at eight in the morning before anybody arrives, which tells you whether the building cleared overnight or started the day already loaded.
2
THE FOUR THINGS THAT CHANGED BETWEEN NINE AND SIX
A door, an extract on a sensor, a damper, and forty fabric seats
One: the entrance door. At eight in the morning it is propped open while housekeeping, staff and deliveries come through, and the hall spends its first two hours on free ventilation that nobody designed and nobody is counting. By ten it is shut, and from then until closing the hall is on mechanical fresh air alone. This is the single most under-noticed item on the list and it has a free test attached: prop the entrance door open for twenty minutes at half past five, with your meter in the hall, and watch the reading. If it falls meaningfully, you have just measured the size of your ventilation shortfall and you have done it for nothing. Two: the toilet extract, and specifically how it is wired. In a great many Indian clinic fit-outs the sanitary extract fan is on the same circuit as an occupancy-sensor light, which means it runs for the three minutes somebody is in the room and is off for the rest of the day. A sanitary extract in a building open twelve hours should run continuously through the opening hours, or at minimum be interlocked to the light with a fifteen-minute run-on timer. That is ₹1,500 to ₹3,500 a fan for the timer, or ₹3,500 to ₹8,000 for a fan that has failed outright, and it matters to your waiting hall because a toilet extract is usually a meaningful part of the whole floor's air movement. Hold a tissue to the grille at nine and again at six: it either sticks or it does not, and it takes four minutes for a floor. Three: the fresh-air damper and the air-conditioning mode. Somebody closed the damper, or set the units to full recirculation, to save on cooling, and they were being responsible rather than careless — but the saving comes directly out of your evening. Confirm the damper is open, confirm the units are not recirculating, and set every indoor unit to run fan-only for the last ten minutes of the day so the coil dries before the building is locked. A damper actuator that has seized is ₹2,500 to ₹6,000. Four: the seating. Forty fabric seats is roughly forty-four square metres of soft, absorbent surface in a hall with about eighty-four square metres of floor. It is the second-largest surface in the room, it is the only large one nobody cleans daily, and it holds what twelve hours of occupancy puts into it and releases it most readily in the afternoon when the hall is at its warmest. Nobody needs to re-upholster this quarter; the point is that perforated or wipeable seating costs about the same as fabric at the next refit and turns that surface into one that gets wiped.
3
WHAT FRAGRANCE CAN AND CANNOT DO ONCE THE AIR IS FIXED
A background is not an air change, and no setting makes it one
I would rather be plain about the limits of my own product than sell you a machine that is going to disappoint you at six in the evening, so here is both halves of it. What fragrance cannot do: it cannot add an air change, because it is not a fan and does not move air. It cannot remove anything — a diffuser adds a small quantity of fragrance material to the air and takes nothing out of it, which is why a diffuser is not an air purifier and why I will not let that sentence be softened. It cannot change what forty fabric seats have absorbed over twelve hours. It cannot make a building with a shut door behave like one with the door propped. And it cannot be turned up to compensate for any of the above: a stronger setting over a hall that is short of air gives your patients two smells instead of one, and they will notice the pair more clearly than they noticed the first. The instruction I give every clinic is that nobody adjusts the machine upward because the room got busy, because busy is an occupancy problem and fragrance makes a crowded room smell of more things rather than fewer. What fragrance can do, once the air is right: hold one low, steady, unremarkable level from opening to closing, so that the hall reads the same at nine as at six and smells of nothing in particular at both. That is presentation and housekeeping, in the same category as the seating, the signage and whether the lift lobby light is working, and it is a legitimate thing to want. The Vaayu at ₹11,999 does it with a 400ml fill lasting about seventy-five days, app control and 1h/4h/8h/24h timers so it runs the opening hours and stops, under 38 dB so a consultation cabin two metres away hears the air conditioning and not the machine, auto-stop, and a key-lock so the setting survives the evening peak. Size it with the same sum you used for the diagnosis, counting only the volumes a door closes, which removes forty to sixty per cent of most clinic plans. What the machine does in a clinic's public areas goes through it, and how a shared waiting area should be scented covers the hall specifically.
The instruction I would give whoever owns the building: get the three counts, the three readings and the one figure from the drawing onto a single sheet before anybody quotes you for anything. If the sheet shows an air-change gap, no fragrance decision you make will survive six in the evening, and the cheapest item on this page — propping a door for twenty minutes — will tell you that in an afternoon.
Nine o'clock against six o'clock, line by line
Print this and fill in the two middle columns yourself, at nine and at six, on an ordinary working day. Every row in it is either free to check or has its correction priced in the last column, and the final row is the only one SOSA sells anything for.
Print this
The same hall, seven hours apart, and what each gap means
| What to check | At nine in the morning | At six in the evening | The correction, and the cost |
|---|---|---|---|
| Occupancy, counted ★ | Six people in a forty-seat hall, staggered first appointments | Fifty people — thirty-eight seated, a dozen standing attendants | ₹0 to count. This is the variable that moved, and fresh air is specified per person |
| The hall's volume | 900 sq ft ÷ 10.76 × 3.2 m = about 268 m³ | 900 sq ft ÷ 10.76 × 3.2 m = about 268 m³. Unchanged | ₹0. The room does not grow to meet the queue |
| Fresh air required, at 8 l/s a person | 48 l/s = 173 m³/h = 0.6 air changes an hour | 400 l/s = 1,440 m³/h = 5.4 air changes an hour | ₹0 to calculate. Ask your contractor for the figure on the drawing and substitute it |
| The entrance door | Propped open since eight for housekeeping, staff and deliveries | Shut since about ten. The hall is on mechanical fresh air alone | ₹0 to test — prop it for twenty minutes at 5:30pm with a meter running. A closer is about ₹500 |
| The toilet extract | Runs for three minutes when the occupancy-sensor light comes on | Still runs for three minutes at a time, in a building twelve hours into its day | A run-on timer ₹1,500–₹3,500 a fan; a failed fan replaced and interlocked ₹3,500–₹8,000 |
| Damper and air-conditioning mode | Nobody has looked. Often closed or recirculating to save on cooling | Same setting, eight times the demand on it | ₹0 to open and reset; a seized damper actuator ₹2,500–₹6,000. Spend order |
| The seating | Forty fabric seats, about 44 m² of soft surface against 84 m² of floor | The same 44 m², twelve hours of occupancy in it, and the warmest part of the day behind it | Perforated or wipeable at the next refit — about the same money, a surface that gets wiped |
| Fragrance | Not a correction for any row above this one | Still not a correction, and a stronger setting gives patients two smells instead of one | Optional, after the air is right. Vaayu ₹11,999, public areas, one low setting, key-locked |
Shop this guide
After the air is right, and not before
The range · last, by choicefrom ₹899Shop → Vaayu · one steady level₹11,999Shop → The lightest scentsfrom ₹299Shop →
The SOSA principle
The hall is the same size at six as it was at nine. The only thing that multiplied by eight was the number of people in it, and fresh air is specified per person. No fragrance setting has ever added an air change, and turning one up over a crowded room adds a smell rather than removing one.
Three counts, three readings, one figure from the drawing, and a door propped for twenty minutes. The whole diagnosis costs ₹3,500 and most of it is free.
What each correction costs, and where fragrance sits in the order
Give yourself two weeks before you decide anything, and give the two weeks a shape, because the measurements are worth more than any single fix. Week one: the three occupancy counts at nine, two and six on three consecutive days; the hall volume written on the same sheet; the fresh-air figure obtained from your air-conditioning contractor; the carbon-dioxide meter bought and an outdoor baseline taken. Week two: readings at the same three hours plus one at eight before anybody arrives, the tissue test at every toilet extract grille at nine and at six, the fresh-air damper confirmed open, the units confirmed not to be recirculating, and the twenty-minute door-prop experiment at half past five with the meter in the hall. At the end of a fortnight you will have a single sheet of paper that either shows an air-change gap or does not, and that sheet is what you take to your facilities contractor instead of an adjective. If the sheet shows the gap, the corrections are in the table above and they run from nothing to about ₹8,000 apiece, with the air-conditioning scope as a renegotiation rather than a new cost. If the sheet does not show a gap — if the readings are flat and the hall is simply not clean — then you have a source rather than a ventilation problem, and the twenty-six-line checklist is the page to work down, starting with the drain traps because a U-bend seal evaporates in two to four weeks of disuse and every clinic has gullies nobody uses.
Two things about the spending order, because this is where facility managers reasonably get frustrated. The first is that almost nothing on this page is a new cost. The damper, the recirculation setting and the fan-off delay are settings. The door-prop test is free and the closer is ₹500. The run-on timer at ₹1,500 to ₹3,500 is small enough to sit under most signature thresholds. The seating is the same money at the next refit, spent on a different material. The air-conditioning maintenance scope widened to name the drain pan, the condensate line and trap, the blower wheel and two chemical coil cleans a year is roughly ₹25,000 to ₹45,000 a year for a ten-unit clinic and is mostly a renegotiation of a contract you already hold. Genuinely new spending here amounts to one meter, one timer and perhaps one fan. The second is that the only item on this page that is truly optional is mine, and I would rather it stayed at the bottom. If you fix the air and the hall then reads the same at nine and at six, you may well decide you want a steady background anyway, and that is a legitimate presentation choice. If you fix the air and the hall reads well without one, you have saved ₹11,999 and I will have done my job. I have had that second outcome often enough to know it is not a rhetorical device, and clinics with fragrance-sensitive patients frequently land there deliberately and are right to.
And then the last line, in the detail somebody signing a purchase order will want. The Vaayu is ₹11,999 and the argument for it in a clinic is a housekeeping argument rather than a clinical one: waterless cold-air nebulisation, so there is no standing water tank to be emptied, rinsed and dried every day by a named person in a building that runs twelve hours. If that person does not exist, do not buy a water tank at all, which rules the ultrasonic Sukoon at ₹1,899, Boond at ₹899 and Megh at ₹3,499 out of public clinical property; those three stay honest for a single administrative cabin where one person owns the daily routine, and the Sukoon arrives with three 15ml Hotel Collection scents included. Coverage up to 1000 cubic metres with the sum done properly — and note that the 268 cubic metre hall you have just measured for the ventilation diagnosis is the same number you use for sizing, counting only the volumes a door closes, which removes forty to sixty per cent of most clinic plans. A 400ml fill lasts about seventy-five days, so roughly five fills a year, and a 300ml refill at ₹1,799 keeps the arithmetic simple at about ₹12,600 a year. The Aangan at ₹25,999 is for an atrium or a whole floor and is overselling in a single 268 cubic metre hall. Run it on one setting for the opening hours, with the key-lock on, and write the numeral in your procedure so that nobody raises it at the evening peak — because the evening peak is the hour this entire page is about, and fragrance is the one tool that does not help with it. Public areas only: entrance, reception, shared and departmental waiting, inter-departmental corridors, lift lobbies, administration and the café corner. Consultation and examination rooms, treatment and procedure rooms, day-care surgery, dressing rooms, sample collection, laboratories, dispensing, sterile stores, imaging, oncology day-care and paediatric clinical areas stay fragrance-free with their doors shut.
The room is the same size at six as it was at nine, and there are eight times as many people in it. No bottle, no machine and no setting has ever solved an arithmetic problem, and this one is arithmetic.
— Sonal Sahani, SOSA
The SOSA edit
The same diagnosis compressed into tiers for a budget meeting, with what each costs and when it earns its place. Two of the six tiers are free, one is a single instrument, and the only SOSA product on the page is at the bottom.
The SOSA edit
Two free tiers, one instrument, and then the optional line
| Tier | What is in it | When it earns its place | Cost |
|---|---|---|---|
| 1. The counts and the sum ★ | Occupancy at nine, two and six on three days; the hall's volume as area ÷ 10.76 × height; the fresh-air figure from your contractor's drawing, all on one sheet | This week. It is the sheet that ends the fragrance-or-ventilation argument in your own building | ₹0 |
| 2. The free settings and the door test | Fresh-air damper confirmed open, units off recirculation, fan-only for the last ten minutes of the day, and the entrance door propped for twenty minutes at 5:30pm | This week, immediately after the counts. The door test alone often sizes the gap | ₹0, plus about ₹500 for a closer |
| 3. The two instruments | A hand-held carbon-dioxide meter as a proxy for air change against occupancy, and a smoke pencil to settle which way air moves through a doorway | This month. A reading in a log is worth more than ten opinions in a meeting | About ₹3,900 together |
| 4. The repairs and the refit | Extract run-on timer ₹1,500–₹3,500 a fan; failed extract fan replaced and interlocked ₹3,500–₹8,000; damper actuator ₹2,500–₹6,000; maintenance scope widened to pan, trap, blower and two coil cleans; wipeable seating at the next refit | This quarter, with dates. Mostly deferred repairs and renegotiations rather than new cost | ₹1,500–₹45,000 |
| 5. Vaayu — optional, and after | Waterless, no standing water tank, up to 1000 m³ against the hall's 268, 400ml lasting about 75 days, app and timers, under 38 dB, key-lock, four scents included | Only once the sheet is flat at nine and at six. Public areas, opening hours, one low setting, written as a numeral | ₹11,999 |
| Not on the list at any price | The machine turned up at the evening peak, a spray at the counter at five, or a stronger bottle because the hall got busy | Never. Busy is an occupancy problem, and holding one level is the point | — |
Honest notes for buyers: the ventilation arithmetic on this page is arithmetic, not a design service — the per-person figure, the installed fresh-air quantity and any remedial work belong to your own mechanical consultant or air-conditioning contractor, and the carbon-dioxide meter described here is used only as a proxy for air change against occupancy and is not a health measurement of any kind. On fragrance itself, fragrance in a medical facility is housekeeping and presentation, never treatment. Nothing here claims that a fragrance reduces anxiety, aids recovery, improves sleep, cleans or disinfects air, or has any clinical effect whatsoever, because it does not and a diffuser is not an air purifier. Scenting belongs to the entrance, reception, shared waiting areas, inter-departmental corridors and administrative rooms. Consultation and examination rooms, treatment and procedure rooms, day-care surgery, dressing rooms, blood- and sample-collection rooms, laboratories, pharmacy dispensing, sterile stores, imaging rooms, oncology day-care and paediatric clinical areas should be left fragrance-free. A persistent smell is information about a dry drain trap, a bin, a soiled-linen route or an air-conditioning drain pan: find it and fix it rather than covering it. On the machines: the Vaayu at ₹11,999 is waterless cold-air nebulisation with no standing water tank, covering up to 1000m³ or roughly 2,000–3,000 sq ft, with a 400ml tank lasting about 75 days, app control, 1h/4h/8h/24h timers, under-38dB running, auto-stop and a key-lock for public areas. The Aangan at ₹25,999 covers up to 3,000m³ and connects to HVAC for a whole floor or an atrium. The ultrasonic Sukoon, Boond and Megh are water-based, hold standing water and add 30–50 ml of water an hour to the air, which suits a single administrative cabin with a named person emptying and drying the tank daily and is unsuitable for public clinical property. An alcohol-free reed diffuser needs 24–72 hours to establish and suits a small lobby rather than a large waiting hall. Candles are not appropriate in a healthcare facility because an open flame is a fire-safety matter. SOSA does not make a room spray. The Hotel Collection scents are SOSA's own interpretations inspired by the world's finest hotels; SOSA is an independent Indian fragrance house, not affiliated with or endorsed by any hotel brand. A portion of every order supports girl-child education through Nanhi Kali.
The optional line, and it stays optional
SOSA Vaayu ₹11,999
Every correction above this one is ventilation, settings or fabric, and most of it is free. This is the only item on the page that SOSA sells and it does not fix a single row of the diagnostic table. What it does, once the air is right, is hold one low, steady, unremarkable level from opening to closing so the hall reads the same at nine as at six. Waterless cold-air nebulisation with no standing water tank, up to 1000 cubic metres against the worked hall's 268, a 400ml fill lasting about seventy-five days, app control with 1h/4h/8h/24h timers, under 38 dB, auto-stop and a key-lock so the setting survives the evening peak. Public areas only, clinical rooms fragrance-free.
SS
ISIPCA
Versailles
Versailles
A note from Sonal
The clinic that taught me to do the sum before the sales call was a polyclinic in Thane whose owner rang me in April describing exactly what you have described, and who had already been quoted for two machines by somebody else. I asked him three questions — how many seats, how many people at six, and what the ceiling height was — and the third one stopped him, because nobody had asked it before and he had to go and find out. When he came back with 900 square feet and 3.2 metres, we did the arithmetic on the phone in about four minutes, and the gap between what six people need and what fifty need was so large that he went quiet. What he actually had was a toilet extract wired to an occupancy-sensor light and an entrance door that had stopped being propped when a new security contractor started in February. The timer cost him under three thousand rupees, and he bought a machine from me eight months later for an entirely different and much better reason.
I have since started asking for the ceiling height in the first two minutes of any call about an evening smell, and it is a strange question from a perfumer. It is also the question that most often ends the conversation, because the moment a hall becomes a number of cubic metres, the person describing it stops talking about atmosphere and starts talking about air, and air is somebody's actual job in their building. Nothing about arriving at the wrong conclusion here is anybody's failure. A room that is pleasant in the morning and not in the evening genuinely feels like a smell problem, and a fragrance supplier is exactly who you would ring. I would just rather be the supplier who hands you a sheet of arithmetic and a thirty-five-hundred-rupee meter, and sells you nothing for a quarter, than the one who sells you two machines in April and hears from you again in May.
I would rather sell one machine into a hall that already holds its air than two into one that does not, because the second kind of customer is unhappy by the evening of the first day and is right to be. Everything is made and supported from Pune, and a part of every order funds girl-child education through Nanhi Kali. You get a space that smells like somewhere looked after; a girl gets a classroom. That equation has always felt right to me.
Frequently asked questions
Is a waiting area that is fine in the morning and unpleasant by evening a fragrance problem or a ventilation problem?
A ventilation and occupancy problem, and the arithmetic shows it. The hall has one volume all day, but fresh-air requirement is specified per person, so a room that goes from six occupants to fifty has multiplied its requirement by more than eight while keeping the same fan and the same ductwork. Fragrance adds no air changes and removes nothing from the air, so it is not the correction, and a stronger setting over a hall short of air simply gives patients two smells instead of one.
How do we prove it without hiring a consultant?
Three things on one sheet. Count everybody in the hall at nine, two and six on three consecutive days. Work out the volume as floor area in square feet divided by 10.76, multiplied by the ceiling height in metres. Then ask your air-conditioning contractor for the fresh-air quantity on the drawing and the per-person figure behind it, and compare the evening requirement with what is installed. A hand-held carbon-dioxide meter from about three and a half thousand rupees turns the whole thing into a log rather than a discussion.
What usually changes between nine in the morning and six in the evening?
Four things, in my experience of walking Indian clinics. The entrance door was propped open for housekeeping and deliveries and has been shut since mid-morning, so the hall went from free ventilation to mechanical fresh air alone. The toilet extract is wired to an occupancy-sensor light and runs three minutes at a time. The fresh-air damper is closed or the units are recirculating, to save on cooling. And forty fabric seats are the second-largest surface in the room and the only large one nobody cleans daily.
What does the carbon-dioxide reading actually tell us?
Only one thing, and it should not be presented as more. Carbon dioxide rises in an occupied room as the air is breathed and falls as fresh air arrives, which makes a reading a proxy for air change against occupancy. Use it to compare the same room at different hours, to see whether the building cleared overnight, and to measure what propping the entrance door for twenty minutes is worth. It is a ventilation instrument. It is not a health measurement, and it does not belong on a notice board or in a conversation with a patient.
Once the ventilation is corrected, is there any point in scenting the hall at all?
There can be, and it is a presentation choice rather than a repair. Once the air holds, a timed machine on one low setting in the public areas keeps the hall smelling of nothing in particular from opening to closing, which is housekeeping in the same category as the seating and the signage. It makes no clinical claim of any kind, a diffuser is not an air purifier, and the clinical rooms stay fragrance-free. A fair number of clinics fix the air and decide they are done, which is a legitimate outcome.
Count the people, then the room
Do the sum before anybody quotes you — and prop the door for twenty minutes at half past five
The Vaayu is ₹11,999 and it belongs after the air is right: waterless cold-air nebulisation with no standing water tank, up to 1000 m³ or roughly 2,000–3,000 sq ft, a 400ml tank lasting about seventy-five days, Bluetooth app control with 1h/4h/8h/24h timers, under 38 dB, auto-stop and a key-lock so the setting survives the evening peak, supplied with four hotel-inspired fragrances. The Aangan is ₹25,999 for 8,000–10,000 sq ft or an atrium, and alcohol-free reeds from ₹749 suit an administrative cabin. Free shipping above ₹499, and a portion of every order supports girl-child education through Nanhi Kali.
See the Vaayu · ₹11,999 All commercial scenting
Continue the read
More from SOSA
- Why does my clinic waiting area smell fine in the morning and stale by evening? — the same pattern, asked without the arithmetic.
- Housekeeping, ventilation, seating and scent: where should a clinic spend first? — the corrections on this page, put as a budget.
- What should a multi-speciality clinic fix before it spends anything on fragrance? — the twenty-six-line checklist for when the readings come back flat.
- How can a clinic hold a consistent fragrance level from opening to closing? — what a machine does hold, once the air holds.
- Brand: the SOSA founder story.
Editorial standards & sources
Product facts used in this guide. SOSA Vaayu Rs 11,999: waterless cold-air nebulising diffuser, no water reservoir, coverage up to 1000m3 (approximately 2,000-3,000 sq ft), 400ml refillable tank lasting up to about 75 days per fill, Bluetooth app plus onboard control, 1h/4h/8h/24h timer scheduling, adjustable intensity, under 38 dB, DC 12V/1A at 5W, 165 x 80.5 x 215 mm and 0.9 kg, freestanding or wall or HVAC mounted, auto-stop and key-lock, CE, RoHS and SGS certified, supplied with four hotel-inspired fragrances. SOSA Aangan Rs 25,999: HVAC-connected or standalone commercial nebulising diffuser, coverage up to 3,000m3 (roughly 8,000-10,000 sq ft), 800ml reservoir, metal body, programmable schedules, under 42 dB. Ultrasonic machines are water-based, hold standing water and consume 30-50 ml of water an hour: Sukoon Rs 1,899 (500ml, 270-320 sq ft, 16-18 hours on low, three 15ml Hotel Collection scents included), Boond Rs 899 (300ml), Megh Rs 3,499 (6 litres). Hotel Collection water-based fragrance 15ml Rs 299, 100ml Rs 999, 300ml Rs 1,799. Alcohol-free reed diffusers from Rs 749, requiring 24-72 hours to reach their working level. Free shipping above Rs 499. Coverage arithmetic: cubic metres equal floor area in square feet divided by 10.76 and multiplied by ceiling height in metres, counting only the volumes that are actually scented. This guide makes no medical, therapeutic or clinical claim of any kind for fragrance: a diffuser does not purify, disinfect or clean air, and does not treat, calm or affect any patient or condition. Fragrance is housekeeping and presentation. Clinical areas should be left fragrance-free, and a persistent odour should be traced to its source and corrected rather than covered. SOSA is not affiliated with or endorsed by any hotel brand. Prices subject to change - see the live product pages.