Ask The Brewmasters

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

I can't answer your specific question about target ppm levels, however, as it takes a lot of air volume to blow out a tank, years ago we started using a shop vac set to 'blow' and it works quite well for this task.  I imagine it's cheaper to run than an air compressor for the same job.

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

Hi Racheal,

A couple thoughts without going through a lot of calculations.

There is no "zero" CO2, because ambient air is 450 ppm+/-. Also, in the States, we have a workplace exposure limit (8-hr all day avg exposure without a respirator) of 5,000 ppm (0.5%). So, if simply for being able to open the manway and have your head near the opening, you'll want to be below 5,000. Canadian exposure limit is also 5,000 ppm (ACGIH).

I know of breweries who make sure the CO2 is below 5,000 before they begin CIP based on the worker health measurement, and none have experienced tank collapse, to my knowledge. I think there is simply too little CO2 to result in sufficient vacuum pressures.

In any case, you will need a CO2 meter to check your tank bleeding process to learn what sort of procedure and time will be required.

I can't answer your specific question about target ppm levels, however, as it takes a lot of air volume to blow out a tank, years ago we started using a shop vac set to 'blow' and it works quite well for this task.  I imagine it's cheaper to run than an air compressor for the same job.

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

I don't know if you have ever done this, but putting your head into a tank with 5000 ppm CO2 is not something I would recommend. That 5000 ppm 8 hr max number is to prevent injury over time, but I have found levels of 1,500 or more can be detrimental to working conditions: headaches, angriness and shortness of breath are commonly observed. Due to these observations, we take additional actions (increased fan velocities, opening doors, etc) whenever levels exceed 1,500 ppm. Typically this will occur during longer can runs, tank purging, and filling of the outside CO2 dewar.

Hi Racheal,

A couple thoughts without going through a lot of calculations.

There is no "zero" CO2, because ambient air is 450 ppm+/-. Also, in the States, we have a workplace exposure limit (8-hr all day avg exposure without a respirator) of 5,000 ppm (0.5%). So, if simply for being able to open the manway and have your head near the opening, you'll want to be below 5,000. Canadian exposure limit is also 5,000 ppm (ACGIH).

I know of breweries who make sure the CO2 is below 5,000 before they begin CIP based on the worker health measurement, and none have experienced tank collapse, to my knowledge. I think there is simply too little CO2 to result in sufficient vacuum pressures.

In any case, you will need a CO2 meter to check your tank bleeding process to learn what sort of procedure and time will be required.

I can't answer your specific question about target ppm levels, however, as it takes a lot of air volume to blow out a tank, years ago we started using a shop vac set to 'blow' and it works quite well for this task.  I imagine it's cheaper to run than an air compressor for the same job.

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

I don't know if you have ever done this, but putting your head into a tank with 5000 ppm CO2 is not something I would recommend. That 5000 ppm 8 hr max number is to prevent injury over time, but I have found levels of 1,500 or more can be detrimental to working conditions: headaches, angriness and shortness of breath are commonly observed. Due to these observations, we take additional actions (increased fan velocities, opening doors, etc) whenever levels exceed 1,500 ppm. Typically this will occur during longer can runs, tank purging, and filling of the outside CO2 dewar.

Hi Racheal,

A couple thoughts without going through a lot of calculations.

There is no "zero" CO2, because ambient air is 450 ppm+/-. Also, in the States, we have a workplace exposure limit (8-hr all day avg exposure without a respirator) of 5,000 ppm (0.5%). So, if simply for being able to open the manway and have your head near the opening, you'll want to be below 5,000. Canadian exposure limit is also 5,000 ppm (ACGIH).

I know of breweries who make sure the CO2 is below 5,000 before they begin CIP based on the worker health measurement, and none have experienced tank collapse, to my knowledge. I think there is simply too little CO2 to result in sufficient vacuum pressures.

In any case, you will need a CO2 meter to check your tank bleeding process to learn what sort of procedure and time will be required.

I can't answer your specific question about target ppm levels, however, as it takes a lot of air volume to blow out a tank, years ago we started using a shop vac set to 'blow' and it works quite well for this task.  I imagine it's cheaper to run than an air compressor for the same job.

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

Hi Racheal,

A couple thoughts without going through a lot of calculations.

There is no "zero" CO2, because ambient air is 450 ppm+/-. Also, in the States, we have a workplace exposure limit (8-hr all day avg exposure without a respirator) of 5,000 ppm (0.5%). So, if simply for being able to open the manway and have your head near the opening, you'll want to be below 5,000. Canadian exposure limit is also 5,000 ppm (ACGIH).

I know of breweries who make sure the CO2 is below 5,000 before they begin CIP based on the worker health measurement, and none have experienced tank collapse, to my knowledge. I think there is simply too little CO2 to result in sufficient vacuum pressures.

In any case, you will need a CO2 meter to check your tank bleeding process to learn what sort of procedure and time will be required.

I can't answer your specific question about target ppm levels, however, as it takes a lot of air volume to blow out a tank, years ago we started using a shop vac set to 'blow' and it works quite well for this task.  I imagine it's cheaper to run than an air compressor for the same job.

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

Hi Matt, thank you so much for the response. That makes a lot of sense that most breweries would vent until below the 8hr exposure limit, and that is also good to hear that this number could potentially be a good baseline for the start of a CIP and not experience tank collapse. 

For clarification, both to you and the group, we are currently using practices to make sure that the atmosphere is safe for workers before opening up the tank. This involves blowing out with compressed air, but unfortunately it can take a long time, especially on our bigger 450hL tanks. I received more clarification from my team about this question, and we were hoping to find out if anyone knew what max level of CO2 could still remain in a tank before CIP could be started, without risking implosion. This would ideally be on a tank that we did not have to open up. The only opening would be the atmosphere lines, but we would like to keep the door closed. The idea is to not let CO2 out into the cellar to raise any atmosphere levels, while also cutting down time on purging with air. Any help is greatly appreciated! Thank you so much!

Hi Racheal,

A couple thoughts without going through a lot of calculations.

There is no "zero" CO2, because ambient air is 450 ppm+/-. Also, in the States, we have a workplace exposure limit (8-hr all day avg exposure without a respirator) of 5,000 ppm (0.5%). So, if simply for being able to open the manway and have your head near the opening, you'll want to be below 5,000. Canadian exposure limit is also 5,000 ppm (ACGIH).

I know of breweries who make sure the CO2 is below 5,000 before they begin CIP based on the worker health measurement, and none have experienced tank collapse, to my knowledge. I think there is simply too little CO2 to result in sufficient vacuum pressures.

In any case, you will need a CO2 meter to check your tank bleeding process to learn what sort of procedure and time will be required.

I can't answer your specific question about target ppm levels, however, as it takes a lot of air volume to blow out a tank, years ago we started using a shop vac set to 'blow' and it works quite well for this task.  I imagine it's cheaper to run than an air compressor for the same job.

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

I can't answer your specific question about target ppm levels, however, as it takes a lot of air volume to blow out a tank, years ago we started using a shop vac set to 'blow' and it works quite well for this task.  I imagine it's cheaper to run than an air compressor for the same job.

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!

Hello everyone, 

I was hoping someone might be able to tell me a recommended maximum ppm value of residual CO2 leftover in a brite tank or storage tank before it is safe to use a caustic wash via CIP? We do not want to risk implosion, or dilute the strength of our caustic cleaner.

Most of the reading I have found just mention purging all the CO2 from the tank, but I was hoping to find out the true definition of "all". Right now we are purging our tanks with compressed air, but there is always a point at the end of the purge where we wonder if the ppm for CO2 has to be zero, or if we can cut it off at a certain point and continue on with the cleaning cycle. 

Thank you!