Hi John, The most effective measure would be cut grooved sch. 40 black steel using Nitrogen as your supervisory gas instead of shop air. This will eliminate the dam effect at the joint. However, the biggest value for your customer will likely be roll grooved sch. 10 black steel and still using Nitrogen as your supervisory gas.
Many arguments can be made about the CRR value which is nothing more than a comparison of the thickness of schedule 40 pipe under the first exposed thread. The "first exposed thread" is the minimum pipe thickness exposed to both interior and exterior corrosion. It occurs at the threaded joint at a line defined by the thread width just before the pipe engages the fitting. There are too many factors to consider when identifying corrosion rates and this ratio is very subjective. Strictly a comparison. As for using Nitrogen as a supervisory gas I think this is definitely the biggest "bang for your buck". In your particular instance Nitrogen provides you with more than just a corrosion mitigation solution. In particular the low dewpoint of 98%+ N2. A typical refrigerated dryer will only get you somewhere around -40°F dew point and 98% Nitrogen will be somewhere around -60°F dew point (that's a 50% increase in humidity reduction). Hope you find this helpful. Andy L. Kaempfer Senior Application Engineer - Fire Protection Systems Bull Moose Tube Company 1819 Clarkson Road Chesterfield, MO 63017 O: 636-812-9276 F: 636-530-5880 M: 314-306-2471 [BullMooseCorporateTagline-black] From: Sprinklerforum [mailto:[email protected]] On Behalf Of John Paulsen Sent: Tuesday, October 3, 2017 12:34 PM To: [email protected] Subject: Schedule 10 vs Schedule 40 pipe Hello Forumites: We are working to develop a bid package for a pair of large freezers and coolers used for food stuffs storage on racks to 35'. The freezers are to be -10 degrees and the coolers will be 31 degrees. The sprinklers systems will be double interlock pre-action with Protecto-wire detection and CMSA sprinklers. My question: The owner is asking for a recommendation on whether to spec schedule 10 or schedule 40 piping. The concern is long term serviceability of the piping system. My initial thought is that due to the constant low ambient temperatures corrosion would be seriously inhibited for two reasons; any condensate in the pipe would be in frozen form and the low temps would inhibit microbial growth. So my thought is that schedule 10 pipe would last the 20 year expected service life of the system. However, I would like to get the thoughts of the forum participants, is the cost of schedule 40 warranted or would schedule 10 service just as well in this application? Thanks in advance for your responses. John Paulsen - SET Crown Fire System Design 6282 Seeds Rd. Grove City, OH 43123 P - 614-782-2438 F - 614-782-2374 C - 614-348-8206 Disclaimer The information contained in this communication from the sender is confidential. It is intended solely for use by the recipient and others authorized to receive it. If you are not the recipient, you are hereby notified that any disclosure, copying, distribution or taking action in relation of the contents of this information is strictly prohibited and may be unlawful. This email has been scanned for viruses and malware, and may have been automatically archived by Mimecast Ltd, an innovator in Software as a Service (SaaS) for business. Providing a safer and more useful place for your human generated data. Specializing in; Security, archiving and compliance. To find out more visit the Mimecast website.
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