Monday, November 24, 2014
Posted by Ankit Chugh on 10:59 AM
Types of Ladders
1) Step Through
2) Side Step
3) Straight/vertical Ladder
· Platforms are provided for access to manholes, instruments, valves and equipment, and for crossovers between ladders.
· The spacing of platforms served by a common ladder shall be in one-foot increments so as to match the rung spacing on the ladders.
· The maximum straight run of ladder is 29'-6" from H.P.F.S. (due to grade variation).
· Projection of nozzles extending through a top platform must be such that the flange bolts are above the platform level.
· Avoid supporting heavy piping loads from platforms (Generally more than 500 pounds).
· Vessel attachments, such as ladder support clips, platform support clips, vessel pipe supports, and guides are generally installed by the vessel fabricator in the shop
· For ladder details (see the figure below), note the 7" minimum toe clearance and 15o maximum ladder slope.
· A ladder with and without a cage has clearance requirements that a designer needs to consider in orienting a vessel.
· The Vessel Group will furnish a ladder and platform standard drawing for piping use
· Platforms used effectively: LG's, TI's, PI's, SC's, PSV's, Valves, accessible from platforms if possible without making platform excessively large.
· No side step off to a common elevation platform on both sides of ladder, unless allowed by job instructions
· Level controller door will open 100o without obstruction.
· Ladders are 16" wide inside, 7" minimum toe clearance, 1'-0" maximum.
· Centerline of ladder to edge of step off is 1'-3".
· Platform used for step-off only at least 2'-6" wide at vessel, i.e. 1'-3" on either side of ladder going up.
Tagged as : Piping Design