Variablen
Table A-2 Efficiencies fr
|
Type Joint |
Description [Note (1)] |
Notes |
fr (Test) |
fr (No Test) |
|
a |
Welded only, a ≥ 1.4t |
(3) |
1.00 |
0.80 |
|
b |
Welded only, t ≤ a < 1.4t |
(3) |
0.70 |
0.55 |
|
b-1 |
Welded only, a < t |
(4) |
0.70 |
… |
|
c |
Brazed, examined |
(5) |
1.00 |
0.80 |
|
d |
Brazed, not fully examined |
(6) |
0.50 |
0.40 |
|
e |
Welded, a ≥ 1.4 t, and expanded |
(3) |
1.00 |
0.80 |
|
f |
Welded, a < 1.4 t, and expanded, enhanced with two or more grooves |
0.95 |
0.75 |
|
|
g |
Welded, a < 1.4 t, and expanded, enhanced with single groove |
0.85 |
0.65 |
|
|
h |
Welded, a < 1.4 t, and expanded, not enhanced |
(3) (7) (8) |
0.70 |
0.50 |
|
i |
Expanded, enhanced with two or more grooves |
(7) (8) (9) |
0.90 |
0.70 |
|
j |
Expanded, enhanced with single groove |
(7) (8) (9) |
0.80 |
0.65 |
|
k |
Expanded, not enhanced |
(7) (8) |
0.60 |
0.50 |
GENERAL NOTE: The joint efficiencies listed in this Table apply only to allowable loads and do not indicate the degree of joint leak tightness.
NOTES:
(1) For joint types involving more than one fastening method, the sequence used in the joint description does not necessarily indicate the order in which the operations are performed.
(2) The use of their (test) factor requires qualification in accordance with A-3 and A-4.
(3) The value of fr(no test) applies only to material combinations as provided for under Section IX. For material combinations not provided for under Section IX, fr shall be determined by test in accordance with A-3 and A-4.
(4) For (no test), refer to UW-20.2(b).
(5) A value of 1.00 for fr(test) or 0.80 for fr(no test) can be applied only to joints in which visual examination assures that the brazing tiller metal has penetrated the entire joint (see UB-14(a)) and the depth of penetration is not less than three times the nominal thickness of the tube wall.
(6) A value of 0.50 for fr(test) or 0.40 for fr(no test) shall be used for joints in which visual examination will not provide proof that the brazing filler metal has penetrated the entire joint [see UB-14(b))
(7) When do /(do - 2t) is less than 1.05 or greater than 1..410, fr shall be determined by test in accordance with A-3 and A-4.
(8) When the nominal pitch (center-to-center distance of adjacent tube holes) is less than do + 2t, fr shall be determined by test in accordance with A-3 and A-4.
(9) The Manufacturer may use other means to enhance the strength of expanded joints, provided, however, that the joints are tested in accordance with A-3 and A-4.