My experience with "Smurf Tube" (ENT) was limited to a single project, where the tubing was used in Post Tension Concrete type floors.
Prior to my arrival on this project, two other people from the Company I was with, installed tubing on lower floors.
We were only installing tubing for HVAC Control systems, not Electrical systems - which was done by another Contractor.
In the Parking levels (below ground level parking), at least half of the smurf runs were unusable - either the 90° elbows were gone, or the tube became filled with Concrete.
At the lowest Parking Level - the one where we had interconnections to ventillation and alarm equipment - in addition to the typical C.O. sensors, over 3/4 of the smurf runs were unusable - resulting in surface mounted EMT runs.
Got to the project right as a floor was ready to be poured, and got to observe the Concrete Crew to learn "What Not To Do".
I ran the tube under the rebar and attached the 90°s against and directly next to the rebar - which kept the tubing and elbows out of the Concrete Crews' footsteps, plus protected it from the Vibrators and the directly falling Concrete from the bucket.
This approach took an additional hour of labor time, and used an additional 25 feet of tube - making the
TOTAL installation time 4 Hours, as opposed to 3 hours; and the total material used 350 Feet, as opposed to 325 Feet.
On floors done by others, maybe 1 run on every other floor could be used - due to Concrete filling the tube; whereas all the runs on the floors I installed could be used.
(FYI: TOTAL Installation time includes time to gather materials + tools, bring up to ground floor level, load to man lift, go up +13 floors, offload materials + tools, install everything, pick up trash and unused materials, load unused stuff + tools to manlift, ride back to ground level, replace unused stuff in material container, log the days' work + inventory, order materials for following week's installation, then log out of the project)Apparently (to a certain Know-Nothing Brown-Nosing Spaz Clown), this was unacceptable!
He figured this should be told to the Company Owner - but told biased in his view only.
That Joker went nuts when I was called into the Office to defend myself, and explain the reasons - In Complexity - just why it was not counterproductive to do the installs my way, but it was extremely counterproductive any other way.
I eventually left the company, because that Joker had it out for me big time following the "Office Meeting With The Boss".
Needless to say, just the very sight of Smurf Tube makes me uncomfortable - if not angry!
Scott35