Sprayball Coverage Test


I am hoping someone would have answers for the following:

We have a stainless steel vessel with 2 sprayballs installed through the nozzles on the top of the tank. Among other certificates and reports, the manufacturer also provided a Sprayball Coverage Test certificate to demonstrate complete coverage of the sprayballs; verified by UV light and riboflavin.

  1. The procedure of the test included completely covering the interior of the vessel with the riboflavin. However, after the rinse bursts through the sprayballs, the procedure only indicated inspecting with UV light of “top head & top head nozzles”. It has no indication of inspecting the rest of the vessel walls, i.e. side and bottom. Is this acceptable as a complete coverage test? If so, why?

  2. What is the riboflavin concentration (in ppm) typically used/recommended for sprayball coverage test? I don’t see any guidance in the ASME BPE. Is there any other standard? I’ve seen 20ppm, 100ppm, 200ppm used from various vendors.


  1. No, I do not think this would be considered an adquate coverage test. I’m assuming your question was whether or not it would be acceptable to leverage the manufacturer’s certificate into IOQ. The supply pressure, supply flow, hose size(s), etc. that are used at the manufacturer may not match what you will use on your site.
  2. We typically use 30 ppm riboflavin solution and don’t have a problem with it. It’s important to store the riboflavin in a dark space or in a closed container so that it does not degrade.

Did the protocol or procedure used for the sprayball test get PRE-Approved by your QA? If you are going to leverage, make sure you get approval beforehand.


Purpose 1 : If you put one or two sprayball in your tank, it is to have continuously wash the PW or WFI tank. In fact, the supplier gives you a certificate to ensure that the top and the nozzles are correctly washed because the rest of your tank (side and bottom) is normally (most of the time) full of water. It is for this reason that the high level in your tank must be just below the spray(s) ball(s) to ensure that you have always a good washing of the side and the bottom, the top and the nozzles are washed by the spray(s) ball(s).
Purpose 2 : I heard that we must prepare a solution of 15 mg/L before aspergation. I think it must be funtion of the UV ligth appartus you use. I don’t know if there is a different among the detection limit of the UV ligth appartus used by your vendors but, if there is a difference, the different concentration you cited migth come from there…

Did you do the test in place with your sprays balls in your tank ? Or did you receive the certificate with the sprays balls ? I recommand you to test the spray ball in your tank and verify that effectively these wash correctly your tank.

I hope I help you.

Thank you all for your insightful inputs and comments.