Hello all, I'm about to take the G3 TSSA exam at the end of the month. Done the whole Algonquin night course thing. I've been working as an illegal gas technician for the past 11 years and figured I should start getting some actual licenses and possibly get somewhere in life instead of helping greedy g2's live like kings.
So here's my question. I went to the website hvacexamguide and have repeatedly taken their free sample g3 test of 30 questions. I notice one particular question comes up about the maximum length of hose permitted for a portable appliance; it states 10' as the correct answer. However; when I open up B149.1 to 6.20.3 on page 48 and read both (a) and (b), I get the impression that 30' is the correct answer for a portable appliance, and that 10' is for a permanent appliance.
I tried contacting them, but their contact information goes straight to an error after a write out my question.
Also, on youtube, he has a video with an error in the sizing of the pipe. I'm just hoping these are errors on his part and no such errors like this will exist on the real TSSA exam. I would hate to fail by a question or 2 based on these errors.
QuoteClause 6.20.3 - When a gas hose is used
(a) for permanent installation, it shall not exceed 10 ft (3 m) in length and shall neither extend from one room to another nor pass through any wall, partition, ceiling, or floor;
(b) for a portable appliance, it shall not exceed 30 ft (9.5 m) unless otherwise stated in the appliance standard;
You're right about a portable appliance allowing a 30' gas hose.
Here's Question 61 from our G3 practice exam,
Quote61. For a natural gas hose what is the maximum length for a portable appliance? (Clause 6.20.3b)
A) 10 feet
B) 25 feet
C) 50 feet
D) 30 feet
You'll have to post a link to the gas piping video so I can see if there's an error.
Since the TSSA is responsible for all the recent changes to the B149 gas code I hope they would also update the exams accordingly.
You should try our G2/G3 practice exams for $20. We also offer a free practice exam here,
http://www.hvactechgroup.com/hvacforum/index.php?topic=622.0
https://www.youtube.com/watch?v=CXddXzA6-aY
In the comments below, it seems there's been a couple posts already in relation to the pipe sizing error.
This video cannot be viewed from a mobile device! LOL
If you want to know how to size gas piping and tubing read this post here,
http://www.hvactechgroup.com/hvacforum/index.php?topic=702.0
Yeah, in that post that's exactly how I've read it and understand it to be done, but how it is wrongly done in the practice exam question is as if the guy is letting this particular branch's total distance not be included as the LMR, but as a shorter run from itself back to the regulator.
Funny thing is, if I was to go around and actually size everybody's house in my area by these methods, half the homes would have undersized piping somewhere.
New builders are constantly piping townhouses and even full sized homes with 3/4" mains.... Good for nothing more than a small furnace and water heater... Only if the LMR is short enough can they dare get away with a 3rd appliance...
You should see the look on a customers face when you tell them you can't install that fireplace they want unless we tear open the ceiling in their basement and charge them another grand to re-do the main line.
They can get away with it because, some seasonal appliances are not used as much, I know some people who use there gas fireplace in the summer and winter but there furnace only runs for the winter season, water heater runs all year, pool heaters run seasonally as well, it is not to often when the pool heater furnace and water heater are all running at the same time.
A couple things to note is Enbridge released a Customer Pipe Sizing (http://www.hvactechgroup.com/files/Pipe%20Sizing.pdf) document that states,
QuoteThe responsibility to ensure that there is appropriate gas pressure and volume to each gas appliance rests solely with the designer/installer.
I do a lot of new construction and would never install less than a 1" gas supply, and most builders specify a 1" gas supply in their scope of work.
If there was ever an incident due to carbon monoxide or an under-fired appliance, the TSSA would certainly verify Table 6.1 of the B149.1-10 was followed and the maximum pressure drop of 1" was not exceeded.
I agree most appliances don't run at the same time, but I would always size the gas line so they can. A lot of manufacturers specify that the gas piping must be sized to allow all appliances to run at the same time, specifically pool heater manufacturers. As per Clauses 4.1.3 and 4.1.4 of the B149.1-10 Gas Code we would have to follow the installation manuals instructions.
QuoteClause 4.1.3 - An appliance, accessory, component, equipment, or any other item shall be installed in accordance with the manufacturer's certified instructions and this Code.
QuoteClause 4.1.4 - Where a conflict exists between the manufacturer's certified installation instructions and this Code, the most stringent of the two shall prevail.
To calculate the gas pressure drop start all appliances and take pressure at gas meter (Pressure A), then with everything still running take pressure at appliance (Pressure B).
Pressure drop is Pressure A - Pressure B.
Do not take pressure at gas meter with everything off as that is not a true pressure. It's only the regulator lockup pressure.
See Table 6.1 for the max allowable gas pressure drop.
At least the one big thing with pool heaters is that they're almost always tied in within 2' of the gas meter, which means it counts as its own system of piping and btu separate from the main feeding the house.
I was also under the impression that Enbridge supplies regulators for the amount of BTU's listed for that use in that home. When you start adding appliances, you're supposed to notify enbridge so that they can verify whether or not they need to up size their regulator. You might have sufficiently upgraded an old home for a whack of future appliances with bigger pipes, but they'll be no good when the reg is maxed out... I can't imagine adding a simple 30mbtu fireplace or dryer would require them upgrading the regulator.
I also remember we came across that scenario with enbridge where they counted the pool heater as seasonal, and separate from the furnace. I find that odd, you can easily still have both fire up at the same time... I do agree that it would be an odd scenario to have a pool heater, dryer, water heater, range (all burners and oven), bbq (on full high for searing steaks), a fire pit, and a fireplace all running full tilt at the same time... But every teacher I've had has told us we have to assume everything is going to run at the exact same time, at its highest btu input.
And speaking of gas supply mains of 3/4", we've had several customers go back on their builder to get the contractors back to install a 1" main into their home... Many of these home owners had it written that their contract it was a "gas ready" home, which implies it's supposed to have sufficient gas supply for more than just a water heater and furnace... Some builders as far back as two years came and upgraded the gas piping for free.... Which is pretty good since our company wouldn't upgrade the most basic re-re to 1" for under a grand.