Page 125 - Pressure Vessel Design Manual

General Design 105

Ladder and Platform (L&P) Estimating
The following is a listing of average breakdowns, both cost and weight, for ladders and platforms (L&Ps) for
refinery-type projects. Note that L&Ps include pipe supports, guides, and davits as well as ladders and platforms.
Because this data is “average,” it is meant to be averaged over an entire project and not to find the cost or weight of
any individual item or vessel.

1. Estimated Price Breakdown:
Platforms 30 PSF Q $2.50/lb = $75/~q ft
Ladders: Caged 241b/ft Q $3.00/lb = $72/ft
Uncaged lOlb/ft Q $2.35/1b = $23/ft
Misc. $2.50/1 b
Handrail: Straight $32/ft
Circular $42/ft

2. Estimated Weight Breakdown (as a breakdown of the total quantity):
Item
- Percentage (%) Cost ($Ab)
Platforms: Circular 3&35% $2.50
Rectangular 5&55% $2.00
Ladders: Caged 7-9% $3.00
Uncaged 2-3% $2.25
Misc. 5-1 0% $2.50

Total 100%

3. Average Cost of L&Ps (assuming 100 tons):
Item Weight (tons) Cost ($1000) Yo (cost)
Platf Circ 31 155 34
Platf Rect 51 204 45
Ladder Caged 8 48 11
Ladder (uncaged) 2.5 11.25 2
8
Misc. 7.5 37.5 -
100T $455.75 100%
Average $/lb = 455.75/100 x 2 = $2.28/1b

4. Average % Detailed Weight Breakdown for Trayed Columns:

Item Large Medium
Ladders 13.1% 9.3%
Framing 33.3 44.2
Grating 25.3 23.5
Handrailing 18.2 9.7
Pipe supports 3.0 1.6
Bolting 2.5 2.5
Davits 4.1 7.4
Misc. 0.5 1.8
100% 100%
5. If no estimate of L&Ps is available, an ROM weight estimate can be determined by taking 5% of the overall
vessel weights for the project as a total L&P weight. A percentage breakdown may be made of this overall
value as noted.