The World Of Evolving Codes

Started by MountainDon, December 04, 2014, 03:25:04 PM

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MountainDon

The World Of Evolving Codes has just hit me. Where I live we now need to install earthquake straps on new water heater tank installations. Plus we need an expansion tank.

The worst earthquake in NM was in 1906... ""Four rebuilt chimneys were shaken off the Socorro County Courthouse, and two others were cracked severely. Plaster fell at the courthouse, and a cornice on the northwest corner of the two-story adobe Masonic Temple was thrown onto its first floor. Several bricks fell from the front gable on one house."  ... USGS report

The expansion tank is to prevent expanding cold water from backing up into the municipal supply or causing a break/leak within the structure. We don't have a back flow preventer in the main supply line; they were not required when the place was built. So this expansion tank won't really do much until such a time the city would force retrofitting.
Just because something has been done and has not failed, doesn't mean it is good design.

hpinson

Well, not to argue for or against the code requirement, but the Rio Grande Valley is a rift valley, stretching from the San Luis valley in Colorado down to El Paso, has a history of (relatively) recent volcanism: the lava flows near Grants date to 8000 years, with 7 not-recent cinder cones just east of Albuquerque, a large volcano to the west (Mount Taylor) and a dormant super-volcano just to the north.  So -- significant earthquake activity, while not recent, is conceivable here, and perhaps is higher than in many other places.

My understanding is that there was an estimated mag. 6.2 earthquake in 1849, and that geologic evidence exists for ones larger than that in the very recent geologic past.  1906 was a 6.2 mag. near Socorro.  Just not a lot of people living in mud houses around to experience it I imagine.

Here are two overviews of seismic events in the RG Valley over the last 150 years or so - one from USGS and the other from NMT.

http://earthquake.usgs.gov/earthquakes/states/new_mexico/history.php

http://geoinfo.nmt.edu/publications/periodicals/earthmatters/9/emv9n1_09.pdf

And a nice map of volcanism in New Mexico from NMMNH: http://nmnaturalhistory.org/albuquerque-volcanic-field.html

Certainly not as risky as parts of California, but not without risk either.


hpinson

Oh and then their is soil liquefaction of the great Rio Rancho sand dune, the Rio Grande alluvium, and the Albuquerque penaplian.  :)

MountainDon

Yes, I'm aware of the low to medium risk. That's one reason I reinforced the cabin piers. I'm just feeling put out by our local government who have made many decisions I disagree with in the past decade.

To the OP I should add that the new code that covers gas pipes now requires a drip leg immediately before each appliance; for us that is the furnace and the water heater. Even though they are side by side they cannot share a common drip leg. No need to retrofit, but the inspector who does water heaters could also demand that be done. It's a grey, iffy area right now. Then there's the $35 permit just to change the old heater for the new. Adding in all the new stuff adds a hundred or so bucks to the cost of replacing a water heater. Not to mention that the space is so cramped full installing the expansion tank will be fun.

Sorry. Rant off.   ;D

Just because something has been done and has not failed, doesn't mean it is good design.

hpinson

Is it for replacement water heaters or new construction only?


MountainDon

The earthquake strapping (2 of them) and the expansion is for replacement as well as new.   The gas pipe drip leg is for new but a local inspector could ask for it for replacement work as well.  RR was first in state to adopt the strap and expansion tank. ABQ is only a step behind.
Just because something has been done and has not failed, doesn't mean it is good design.

Onkeludo2

Quote from: MountainDon on December 04, 2014, 06:33:59 PM
To the OP I should add that the new code that covers gas pipes now requires a drip leg immediately before each appliance; for us that is the furnace and the water heater. Even though they are side by side they cannot share a common drip leg. No need to retrofit, but the inspector who does water heaters could also demand that be done. It's a grey, iffy area right now.

Most experts have even discredited the need for a drip leg in modern natural gas systems (LP is STILL debated!).

Oddly I live the land of Archiac Codes where things change slowly.  Some of this is good but some in mind boggling:

Until 2 years ago all use of NM/NM-B was not code in Residential work...anywhere in the county...though modular homes were exempt due to their unique status.  Now it is allowed for "the extension of an existing branch circuit where the use of rigid conduit is unfeasible and the wire will be well protected".  Metal outlet boxes are still required indoors.

Copper water pipe is approved and galvanized is still approved but PEX was only accepted this year (and only crimp-ring fittings).

And the list goes on...

Making order from chaos is my passion.

flyingvan

I'm OK with the water heater strapping, but to require them on tankless water heaters is silly and exemplifies everything that's wrong with the code process.  Doing something ridiculous just to comply is wasteful, but the path of least resistance
Find what you love and let it kill you.

rick91351

It really makes me wonder about all the lobbying that goes on to change things.   
Proverbs 24:3-5 Through wisdom is an house builded; an by understanding it is established.  4 And by knowledge shall the chambers be filled with all precious and pleasant riches.  5 A wise man is strong; yea, a man of knowledge increaseth strength.


JRR

#9
Over to the right, here in Georgia, we have had the "drip leg" requirement on gas lines for a few years now.  It is for any device that has an automatic gas control valve.  The concern is that a small metal filing, or piece of rust, might find its way into the valve workings and prevent it from closing... and this might go unnoticed.  Bang!  The "drip leg" allows such debris to fall out of the stream just before the controls.
.
If you want more on the "drip leg", you can dig through following.  (I think the "leg" is re-named a "sediment trap"):
http://www.gpta.net/Classes/Gas%20Pipe%20Install/gas%20installation.pdf