NATIONAL CRANE
Published 03-23-2018 Control # 243-14
2-9
NBT50 OPERATOR MANUAL
SAFETY PRECAUTIONS
2
Calculate
Allowable Load
Lifting is not permitted.
Cease Lifting Operations
.
Plan the lift when
V(z)
< calculated
Maximum Permissible Wind Speed.
It is permissible to lift
Allowable load
at this windspeed,
V(z)
Maximum Permissible
Wind Speed > V(z)?
YES
YES
NO
NO
NO
V(z) =
3 second gust wind speed at boom tip, m/s (mph)
Ap
= Projected Wind Area of Load, m
2
(ft
2
)
Determine
Maximum Permissible Wind
Speed
Awr
(Allow)
>Awr
(load) ?
Awr
(load)
= Actual Wind Resistance Area for the Load, m
2
(ft)
Awr
(Allow)
= Allowable Wind Resistance Area of the Load, m
2
(ft2
Cd
= air drag coefficient of load
Calculate
Awr
(load)
= Ap X Cd
Determine
Cd
of Load
Ap
= maximum height X maximum length
Lifting is not permitted.
Cease Lifting Operations
V(z)
> 20.1 m/s (45 mph)
13.4 m/s <
V(z)
< 20.1 m/s
(30 mph <
V(z)
< 45 mph)
Use Main Boom on
Fully Extended Outriggers ONLY
V(z)
< 13.4 m/s (30 mph)
Main Boom
Allowable load =
Published Rated Capacity
Allowable Load = Published Rated Capacity
X Capacity Reduction Factor
(from Load Chart Notes)
Determine
Ap
Ap / Allowable Load
< 0.5 m
2
/t ?
(Ap / Allowable Load
< 0.0025 ft
2
/lb)
Awr
(Allow)
= 1.2 m
2
/t
(Awr
(Allow)
= 0.0059 ft
2
/lb)
From Table 2-2
Calculate
Awr
(Allow)
of allowable load
YES
Calculate Ratio:
Awr
(load)
/ Awr
(Allow)
From (Table 2-3)
Determine 3-Second Gust
Wind Speed at boom tip,
V(z)
V(z) =
[(
z
/10)
0.14
+ 0.4]
v
[m/s]
V(z) =
[(
z
/33)
0.14
+ 0.4]
v
[mph]
FIGURE 2-1
Simplified Method to Determine Maximum Permissible Wind Speed
Содержание National Crane NBT50 Series
Страница 1: ...Operator Manual National Crane NBT50 Series ...
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Страница 10: ...TOC 6 TABLE OF CONTENTS OPERATOR MANUAL NBT50 THIS PAGE BLANK ...
Страница 12: ...INTRODUCTION OPERATOR MANUAL NBT50 1 2 Published 03 23 2018 Control 243 14 FIGURE 1 1 7650 66 ...
Страница 50: ...2 36 Published 03 23 2018 Control 243 14 SAFETY PRECAUTIONS NBT50 OPERATOR MANUAL 8496 1 FIGURE 2 6 ...
Страница 82: ...CONTROLS AND OPERATING PROCEDURES OPERATOR MANUAL NBT50 3 22 Published 03 23 2018 Control 243 14 FIGURE 3 14 ...
Страница 134: ...MAINTENANCE CHECKLIST OPERATOR MANUAL NBT50 6 12 Published 03 23 2018 Control 243 14 THIS PAGE BLANK ...
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