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Evans38004  
#1 Posted : 21 July 2022 07:05:47(UTC)
Rank: Forum user
Evans38004

Morning all,

A client has a chemical blending area ~30m x 15m x 3m with very little ventilation (two entry doors either end)

They use hydrochloric acid and caustic soda to clean tanks / pipework 

Employees are concerned when they see metal surfaces rusting & plastic pipes becoming brittle prematurely 

I've checked EH40 and can find the STEL / WEL levels, so the next step (I think) is to ascrtain the concentrations of these chemicals in the atmosphere during maintenance / normal operation.

I've receied had a quote for £1300 for a full analyis - but would like to get a quick and cheap test of  approx levels of concentrations at this stage - I can find draeger tubes for HCl (<£100), but nothing for Caustic Soda.

Any suggestions on how to proceed? 

Roundtuit  
#2 Posted : 21 July 2022 07:46:26(UTC)
Rank: Super forum user
Roundtuit

Originally Posted by: Evans38004 Go to Quoted Post
Employees are concerned when they see metal surfaces rusting & plastic pipes becoming brittle prematurely

I would be looking for an engineer to give a materials compatability assessment - prematurely ageing plastic pipes sounds like a pre-cursor to injury.

They would need the specificatio for the materials of construction, the concentration/temperature/pressure of the cleaners in use along with the concentration/temperature/pressure of the standard materials.

Roundtuit  
#3 Posted : 21 July 2022 07:46:26(UTC)
Rank: Super forum user
Roundtuit

Originally Posted by: Evans38004 Go to Quoted Post
Employees are concerned when they see metal surfaces rusting & plastic pipes becoming brittle prematurely

I would be looking for an engineer to give a materials compatability assessment - prematurely ageing plastic pipes sounds like a pre-cursor to injury.

They would need the specificatio for the materials of construction, the concentration/temperature/pressure of the cleaners in use along with the concentration/temperature/pressure of the standard materials.

jonathandaniels  
#4 Posted : 21 July 2022 08:58:18(UTC)
Rank: Forum user
jonathandaniels

Just an observation, what chemicals are actually being blended in this plant? Both HCI and NaOH can be quite reactive with many other chemicals, metals and each other, you may need to be concerned with the generation of other hazardous substances and even flammable gases.

antbruce001  
#5 Posted : 21 July 2022 14:01:36(UTC)
Rank: Forum user
antbruce001

You haven't mentioned the concentration of acid and casutic being used. For cleaning, relatively low concentrations are normally used. 

I don't think you have exposure level issues. Caustic is only a problem as a dust, so you don't get inhalation issues with solutions of caustic. HCl is only really an inhalation problem at high concentrations. 

The main issue is the compatability issues with the plant itself. HCl will attack metal, resulting in corrosion and caustic is not that good for plastics. There is also compatability issues between the caustic and the acid, so this is another potential risk area.

I think the cleaning processes needs a rethink!

thanks 2 users thanked antbruce001 for this useful post.
Kate on 21/07/2022(UTC), A Kurdziel on 27/07/2022(UTC)
marcw330@googlemail.com  
#6 Posted : 22 July 2022 14:39:54(UTC)
Rank: Forum user
marcw330@googlemail.com

As other have said, there is a little more too this. We need to know the concentrations, what chemicals are being blended and what is the HCl and NaOH being used to clean and are these being mixed? 

Initial thought is that there is always another product to be used to clean, especially one that wont damage the pipes, these may have to be explored. 

A Kurdziel  
#7 Posted : 27 July 2022 12:51:38(UTC)
Rank: Super forum user
A Kurdziel

“They use hydrochloric acid and caustic soda to clean tanks / pipework” what does that actually mean? Do you simply flush a solution of HCL or NaOH through the tanks pipework or are they actually pouring onto external surfaces and rubbing it down with a cloth. What concentrations are you using? Finally you can’t mix the two solutions together since they will react, possible violently and leave you with a  rather useless salt solution.

 

 

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