Why do I keep finding this detail on a waste branch? Seems wrong!

[Ric2013]

I keep coming across connexions to SVPs being made by two knuckle bends into the SVP almost or even just below floor level. This is clearly not to prevent crossflow, as I'm seeing it even where there are no nearby connexions to the SVP at all. My hunch is that it is the result of non-qualified contractors putting in the SVP and adding bosses where they think they may be required (i.e. as low as possible, which ends up being below the floor screed level). The plumber then connecting uses two knuckle bends to allow the slight offset required to bring a branch pipe out to meet the centre of the SVP which is farther from the wall surface due to its greater diameter.

(first photo - apologies for the 2" pipe with 1.5" knuckle bends, but you get the idea!):

This results in my being called due to the blockages that follow this kind of detail.

Is a valid technical reason that I am missing that this detail is better than what I would be inclined to do which is form an offset with 2 obtuse bends? or that my proposed detail (which, in this particular case is higher above the rest bend too) is especially wrong?

(second photo):

Many thanks for anyone's input!

 

[Deleted member 120897]

I’d be more concerned with the lack of safety footwear, or are they steel toe capped socks? 😂

Getting back on point, iirc, tight bends shouldn‘t be used where possible anyway, regardless of position. It might be as you suspect, whereby other contractors are involved, or perhaps untrained plumbers, or even multi skilled men? (We have those, and they’re being paid plumbers rate 😳).

 

[Ric2013]

I’d be more concerned with the lack of safety footwear, or are they steel toe capped socks? 😂

Getting back on point, iirc, tight bends shouldn‘t be used where possible anyway, regardless of position. It might be as you suspect, whereby other contractors are involved, or perhaps untrained plumbers, or even multi skilled men? (We have those, and they’re being paid plumbers rate 😳).

No, that was a staged photo for illustrative purposes taken in my house, which is very much unfinished but more urgent distractions came up lol. And In the context of my making the risk assessment, the weight of the plastic fittings was insufficient to warrant steel toecaps. Though socks are probably a slip hazard!

Getting back on point then, there is no reason to retain such horrible detailing, that you are aware of?

 

[Deleted member 120897]

Getting back on point then, there is no reason to retain such horrible detailing, that you are aware of?

No, certainly not. I only use them where it warrants it or I’m told by my employer.

 

[mfgs]

Its definitely not the ideal way of connecting on to a stack, a couple of 45's as shown above is how I like to make connections. I try to avoid knuckle bends where possible on waste runs.

 

[SimonG]

Prefer a couple of 45's. More functional and easier to rod if needs be.

 

[king of pipes]

Just bad practice I'd say far far better to use 45° fittings . Kop