What is the maximum allowable deflection between the span for the tubes according to a boiler code?
What is the maximum allowable deflection between the span for the tubes according to a boiler code?
(OP)
Another related question, is it necessary to use hot modulus to calculate the deflection? The hot gases are flowing around the tubes, and there is hot water at high pressure inside the tubes.





RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
Separate from gravity loads is the vibratory deflection caused by fluid elastic forces , and that deflection would be limited based on high cycle fatigue requirements.
"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
If you do not calculate sag and/ or bending e.g. by means a flexibility or pipe stress analysis, table 121.5 can be used. Nevertheless, the amount of deflection should not impose any stress greater than the Code allowable.
As per your 2nd question
As your calculating displacement stresses for deflection, youre not allowed to use the hot modulus, unless otherwise justified. If the hot modules provides a greater sag with a greater detrimental effect, I would imagine you could opt for using the hot modulus, if so allowed by the governmental jurisdiction and the owner.
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
The boiler is an economiser (water tube boiler). ASME-I doesn't explicitly mention sagging or bending stress, however, looking at PG-22 Loadings it requires to consider any additional loading, hence bending stress needs to be considered.
Again, I can't find anywhere on how to consider it in ASME-I but I have found out that it's being considered in B31.1.
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?
"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick
RE: What is the maximum allowable deflection between the span for the tubes according to a boiler code?