Effects of Cold Front on Internet Infrastructure - U.S. Midwest

Thu Jan 31 20:21:58 UTC 2019

Mel;

You are absolutely right. I should have been more specific in my
description of the problem.

On Thu, Jan 31, 2019 at 1:27 PM Mel Beckman <mel at beckman.org> wrote:

> Fletcher,
>
> I don’t think that’s true. I find no specs on fiber dB loss being a
> function of ambient temperature. I do find fiber optic application data
> sheets for extreme temperature applications of -500F and +500F
> (spacecraft). You’d think if temperature affected fiber transmission
> characteristics, they’d see it in space.
>
> What you likely were seeing was connector loss, owing either to improper
> installation, incorrect materials, or unheated regen enclosures.
>
> Insertion loss (IL) failures, for instance, in the cold are a direct
> result of cable termination component shrinkage. That’s why regen and patch
> enclosures need to be heated as well as cooled.
>
> All fiber termination components have stated temperature limits. As
> temperatures approach -40F, the thermoplastic components in a
> cable's breakout, jacketing, and fiber fanout sections shrink more than the
> optical glass. Ruggedized connectors help somewhat, but the rule is that
> you can’t let optical connectors and assemblies get really cold (or really
> hot).
>
> A typical spec for a single-mode OSP connector is:
>
> Operating -30C (-22F) to +60C (+140F)
>
> The range for the corresponding Single Mode fiber is:
>
> Operating -55C (-67F) to +70C (+158F)
> Storage -60C (-76F) to +70C (+158F)
> Installation -30C (-22F) to +50C (+122F)
>
> All professional outside plant engineers know these requirements. So if
> you’re seeing failures, somebody is breaking a rule.
>
>  -mel
>
>
> On Jan 30, 2019, at 3:05 PM, Fletcher Kittredge <fkittred at gwi.net> wrote:
>
>
> Cold changes the transmission characteristics of fiber. At one point we
> were renting some old dark fiber from the local telephone company in
> northern Maine. When it would get below -15%-degree F the dB would get bad
> enough that the link using that fiber would stop working. The telephone
> company was selling us dark fiber because regulation required them to. They
> refused to give us another fiber nor inspect/repair. They took the position
> they were required to sell us fiber, not working fiber.
>
>
> On Wed, Jan 30, 2019 at 11:41 AM Mark Tinka <mark.tinka at seacom.mu> wrote:
>
>> For anyone running IP networks in the Midwest, are you having to do
>> anything special to keep your networks up?
>>
>> For the data centres, is this cold front a chance to reduce air
>> conditioning costs, or is it actually straining the infrastructure?
>>
>> I'm curious, from a +27-degree C summer's day here in Johannesburg.
>>
>> Mark.
>>
>
>
> --
> Fletcher Kittredge
> GWI
> 207-602-1134
> www.gwi.net
>
>
>

-- 
Fletcher Kittredge
GWI
207-602-1134
www.gwi.net
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