1. #1
    Forum Member
    1OLDTIMER's Avatar
    Join Date
    May 2008
    Location
    USAF 389th SAC
    Posts
    255

    Default Tanker 'Roll overs':

    Ashley, Indiana Fire Dept. pumper truck rolls!!

    This is a few months old, however I think it may be a good 'training' tool for drivers.

    Cause could be driving too fast...not considering the sudden 'shift' of the H2O the tank when conering.

    http://www.youtube.com/watch?feature...&v=ksFNWl3QidQ


    Name:  Ashley, IN. Tanker.jpg
Views: 1159
Size:  24.7 KB-------------------------------------------------------------------------------
    Here is another recent tanker 'roll over'

    Tuesday, March 20, 2012 Emergency crews responded to an overturned fire truck Monday afternoon in Madison County, Miss.

    http://www.emergencyvehicleresponse....ayoutfile/home
    Last edited by 1OLDTIMER; 03-22-2012 at 04:01 PM.
    "we will bankrupt ourselves in the vain attempt at absolute security"
    Pres. / General Dwight D. Eisenhower

  2. #2
    Forum Member

    Join Date
    Nov 2002
    Posts
    1,165

    Default

    Good topic. I've seen where a lot of old heads have even rolled a tanker. Good reminder that we all need to keep up on training.
    We are recieving a new engine/tanker around the first of August. We will require driver/operator training before FF's can drive it on a run. I'm thinking there will be about 5-6 hours required before a driver is qualified. It will also be the last truck they qualify to drive, as it will be the biggest. There's four other trucks they have to qualify on first, not counting our grass truck.

  3. #3
    Forum Member
    EastKyFF's Avatar
    Join Date
    Feb 2001
    Posts
    3,088

    Default

    I'm not happy with the configuration of that truck. It looks like a very high center of gravity, and a rectangular tank exacerbates the problem. It does look like speed is a factor too.

    On a side note, I was really touched to see all the civilians running over to help. You see so many videos and photos these days of people not willing to get involved, so it's nice to see Small Town USA acting this way. I hope the crew is OK.
    "Be polite, be professional, but have a plan to kill everybody you meet.
    --General James Mattis, USMC


  4. #4
    Forum Member

    Join Date
    Nov 2002
    Posts
    1,165

    Default

    Quote Originally Posted by EastKyFF View Post
    I'm not happy with the configuration of that truck. It looks like a very high center of gravity, and a rectangular tank exacerbates the problem. It does look like speed is a factor too.

    On a side note, I was really touched to see all the civilians running over to help. You see so many videos and photos these days of people not willing to get involved, so it's nice to see Small Town USA acting this way. I hope the crew is OK.
    I'd say as new as that tanker is, some engineering went into it as far as the center of gravity. But regardless of that, excessive speed will overcome center of gravity no matter how low it is.

  5. #5
    Forum Member

    Join Date
    Nov 2007
    Posts
    600

    Default

    Quote Originally Posted by EastKyFF View Post
    I'm not happy with the configuration of that truck. It looks like a very high center of gravity, and a rectangular tank exacerbates the problem. It does look like speed is a factor too.
    Please explain why you think a rectangular tank would exacerbate the problem. It would seem to me that a properly baffled rectangular tank would have a lower center of gravity than most tank shapes that are also properly baffled.

    Physics being physics, I am interested in your slant on things.

  6. #6
    Back In Black
    ChiefKN's Avatar
    Join Date
    Feb 2003
    Location
    The Nice Part of New Jersey
    Posts
    6,981

    Default

    Speed...

    Regardless of other factors, slowing down would've prevented this.

    I always tell the guys that there is just no urgent need for the tanker. It gets there when it gets there.
    I am now a past chief and the views, opinions, and comments are mine and mine alone. I do not speak for any department or in any official capacity. Although, they would be smart to listen to me.

    "The last thing I want to do is hurt you. But it's still on the list."

    "When tempted to fight fire with fire, remember that the Fire Department usually uses water."

  7. #7
    MembersZone Subscriber

    Join Date
    Jan 2007
    Location
    Pa Wilds
    Posts
    586

    Default

    Tanker Rollover

    Looking at the video, I made some measurements and calculations as follows:

    1. The video timer is real time and correct.
    2. Roadway is 24 ft. from curb to curb and the distance from curb to centerpoint of the radius is another six feet giving a radius of curvature of 30 feet.
    3. It takes the truck six seconds to round the curve of 188 ft (1/4 circumference)
    4. The truck is traveling at 31 feet per second or 21 MPH
    5. The acceleration will be velocity squared divided by the radius 31 x 31 / 30 = 32 ft/sec squared
    6. Acceleration divided by 32 ft (1 G) or 32 / 32 + 1G so the radial force will be equal to the weight of the truck
    7. Next question is..Where is the center of gravity compared to the width of the wheelbase.
    8. I used the picture standing still and estimated the height at 110 inches at top of tank
    9. Looking at the picture my guess is the center of gravity is about 70 inches above the roadway.
    10. Width of the wheels is around 100 inches, so the pivot point is 50 inches from the center of gravity. (looking directly at the rear of the tanker.) It will take a force of 50 / 70 G’s to turn this truck over. This is 0.707 G for this turn.
    11. Reversing the calculations The maximum speed for this curve would be 26 ft / sec or 18 MPH.
    12. If the car were not in the intersection, and the driver spread the curve by coming to the inside in the middle of the turn (making the curve longer) the radius could be stretched to a 40 ft radius. This would result in 0.75G or just slightly above the turn over point. He was still too fast for the turn.
    13. This tanker illustrates why the center of gravity is a critical specification on heavy apparatus. Tankers, aerials, cranes, etc. Slow it down! 20 MPH seems like a crawl after you have been running at 40 or more on the straight away.

  8. #8
    Forum Member
    1OLDTIMER's Avatar
    Join Date
    May 2008
    Location
    USAF 389th SAC
    Posts
    255

    Default

    Please explain why you think a rectangular tank would exacerbate the problem. It would seem to me that a properly baffled rectangular tank would have a lower center of gravity than most tank shapes that are also properly baffled.
    I don't know for sure, but how many 'other type' of tank vehicle(s) do you see with rectangular tanks...i.e., petro, milk etc, must be good reason...?
    "we will bankrupt ourselves in the vain attempt at absolute security"
    Pres. / General Dwight D. Eisenhower

  9. #9
    Back In Black
    ChiefKN's Avatar
    Join Date
    Feb 2003
    Location
    The Nice Part of New Jersey
    Posts
    6,981

    Default

    Quote Originally Posted by 1OLDTIMER View Post
    I don't know for sure, but how many 'other type' of tank vehicle(s) do you see with rectangular tanks...i.e., petro, milk etc, must be good reason...?
    A rectangular tank on its own is no more dangerous than a round or elliptical tank.

    It is ALL about the baffles and center of gravity.

    Many milk tankers have NO baffles for sanitary (sterlizing) reasons.
    Last edited by ChiefKN; 03-25-2012 at 02:13 PM.
    I am now a past chief and the views, opinions, and comments are mine and mine alone. I do not speak for any department or in any official capacity. Although, they would be smart to listen to me.

    "The last thing I want to do is hurt you. But it's still on the list."

    "When tempted to fight fire with fire, remember that the Fire Department usually uses water."

  10. #10
    Forum Member

    Join Date
    Nov 2002
    Posts
    1,165

    Default

    Quote Originally Posted by 1OLDTIMER View Post
    I don't know for sure, but how many 'other type' of tank vehicle(s) do you see with rectangular tanks...i.e., petro, milk etc, must be good reason...?
    Milk and gas tankers don't carry ladders, 5" hose, dump tanks, etc. The reason for square tanks is to accommodate more equipment. Elliptical tankers sacrifice storage space for water capacity.

  11. #11
    Forum Member
    1OLDTIMER's Avatar
    Join Date
    May 2008
    Location
    USAF 389th SAC
    Posts
    255

    Default

    Quote Originally Posted by johnsb View Post
    Milk and gas tankers don't carry ladders, 5" hose, dump tanks, etc. The reason for square tanks is to accommodate more equipment. Elliptical tankers sacrifice storage space for water capacity.
    Thanks, but I guess THIS is what I had in mind as a 'tanker', and it looks like it has a elipitical tank, a dump tank, with a good size pump, etc., but I cannot see why a (real) tanker has a need for ladders.

    However, I was ref; to a tanker not a tanker/pumper. Maybe I am not on the same page...as usual...

    Name:  BluegrassTanker.jpg
Views: 880
Size:  31.8 KB
    Last edited by 1OLDTIMER; 03-25-2012 at 05:48 PM.
    "we will bankrupt ourselves in the vain attempt at absolute security"
    Pres. / General Dwight D. Eisenhower

  12. #12
    Forum Member

    Join Date
    Apr 2004
    Location
    Bossier Parrish, Louisiana
    Posts
    10,597

    Default

    Quote Originally Posted by 1OLDTIMER View Post
    Thanks, but I guess THIS is what I had in mind as a 'tanker', and it looks like it has a elipitical tank, a dump tank, with a good size pump, etc., but I cannot see why a (real) tanker has a need for ladders.

    However, I was ref; to a tanker not a tanker/pumper. Maybe I am not on the same page...as usual...

    Attachment 21946
    In LA, many rural departments use the storage space afforded by a rectangular tank for stuff - saws, airpacks, spare cylinders, salvage covers, fans, pike poles and ladders - so that it can be claimed as a service truck on the rating.
    Train to fight the fires you fight.

  13. #13
    MembersZone Subscriber

    Join Date
    Sep 2005
    Location
    So of Can. / N. of Mexico
    Posts
    869

    Default

    The recent 2009 edition of NFPA1901 requires that if a tanker, or any truck for that matter, cannot make a 50% tilt table test, the chassis must be equipped with electronic stability control. That may not have prevented this particular accident but it would have raised the threshold at which it occured.
    As a result, more tankers look like the attached version with a long low tank and the water pump located under the water tank for a lower center of gravity.
    Attached Images Attached Images  

  14. #14
    Forum Member

    Join Date
    Nov 2002
    Posts
    1,165

    Default

    Quote Originally Posted by 1OLDTIMER View Post
    Thanks, but I guess THIS is what I had in mind as a 'tanker', and it looks like it has a elipitical tank, a dump tank, with a good size pump, etc., but I cannot see why a (real) tanker has a need for ladders.

    However, I was ref; to a tanker not a tanker/pumper. Maybe I am not on the same page...as usual...

    Attachment 21946
    Well I'm probably a bit biased right now because we just bought a pumper/tanker, but if we had a larger district without any hydrants, that truck would be nice to have!

  15. #15
    Forum Member

    Join Date
    Oct 2000
    Location
    KENTUCKY
    Posts
    410

    Default

    Quote Originally Posted by KuhShise View Post
    Tanker Rollover

    Looking at the video, I made some measurements and calculations as follows:

    1. The video timer is real time and correct.
    2. Roadway is 24 ft. from curb to curb and the distance from curb to centerpoint of the radius is another six feet giving a radius of curvature of 30 feet.
    3. It takes the truck six seconds to round the curve of 188 ft (1/4 circumference)
    4. The truck is traveling at 31 feet per second or 21 MPH
    5. The acceleration will be velocity squared divided by the radius 31 x 31 / 30 = 32 ft/sec squared
    6. Acceleration divided by 32 ft (1 G) or 32 / 32 + 1G so the radial force will be equal to the weight of the truck
    7. Next question is..Where is the center of gravity compared to the width of the wheelbase.
    8. I used the picture standing still and estimated the height at 110 inches at top of tank
    9. Looking at the picture my guess is the center of gravity is about 70 inches above the roadway.
    10. Width of the wheels is around 100 inches, so the pivot point is 50 inches from the center of gravity. (looking directly at the rear of the tanker.) It will take a force of 50 / 70 Gs to turn this truck over. This is 0.707 G for this turn.
    11. Reversing the calculations The maximum speed for this curve would be 26 ft / sec or 18 MPH.
    12. If the car were not in the intersection, and the driver spread the curve by coming to the inside in the middle of the turn (making the curve longer) the radius could be stretched to a 40 ft radius. This would result in 0.75G or just slightly above the turn over point. He was still too fast for the turn.
    13. This tanker illustrates why the center of gravity is a critical specification on heavy apparatus. Tankers, aerials, cranes, etc. Slow it down! 20 MPH seems like a crawl after you have been running at 40 or more on the straight away.
    I agree with KuhShise: Pilot Error.

  16. #16
    Forum Member

    Join Date
    Nov 2007
    Posts
    600

    Default

    Quote Originally Posted by 1OLDTIMER View Post
    I don't know for sure, but how many 'other type' of tank vehicle(s) do you see with rectangular tanks...i.e., petro, milk etc, must be good reason...?
    Over the road trucks use oval or round tanks because they are easier to build and less seams. It has absolutely nothing to do with center of gravity. For any given capacity and a fixed length, the oval or round tank will have a higher center of gravity.

  17. #17
    Forum Member

    Join Date
    Nov 2007
    Posts
    600

    Default

    Found some information on the DOT website that pertains to rollover accidents. It comes from a study of tank truck rollovers that was released May, 2008.

    Over 1,300 cargo tank rollovers are reported each year.

    31% of all fatal commercial truck rollovers involve cargo tanks.

    93% of cargo tank rollovers occur on dry road surfaces.

    Over 50% of cargo tank rollovers involve leaving the road.

    28% of cargo tank accidents involve driving too fast for conditions.

    44% of cargo tank rollovers occur on curves (56% on straight roads.)

    25% of cargo tank rollovers involve straight trucks.

    66% of cargo tank rollovers involve drivers with more than ten years driving experience.

    78% of cargo tank rollovers involve some kind of driver error.

  18. #18
    Forum Member
    1OLDTIMER's Avatar
    Join Date
    May 2008
    Location
    USAF 389th SAC
    Posts
    255

    Default

    Quote Originally Posted by firepundit View Post
    Found some information on the DOT website that pertains to rollover accidents. It comes from a study of tank truck rollovers that was released May, 2008.

    Over 1,300 cargo tank rollovers are reported each year.

    31% of all fatal commercial truck rollovers involve cargo tanks.

    93% of cargo tank rollovers occur on dry road surfaces.

    Over 50% of cargo tank rollovers involve leaving the road.

    28% of cargo tank accidents involve driving too fast for conditions.

    44% of cargo tank rollovers occur on curves (56% on straight roads.)

    25% of cargo tank rollovers involve straight trucks.

    66% of cargo tank rollovers involve drivers with more than ten years driving experience.

    78% of cargo tank rollovers involve some kind of driver error.
    Good data. I find this VERY interesting, especially that 78% involve (some type of) 'driver error', and that 93% occur on 'dry' road surfaces.

    I wonder if this equates to; not paying attention, and not considering the weight/height of the vehile while cornering or exiting on ramps? A less than full tank (like when returning) will overturn easier than a when full.
    "we will bankrupt ourselves in the vain attempt at absolute security"
    Pres. / General Dwight D. Eisenhower

  19. #19
    Forum Member

    Join Date
    Nov 2002
    Posts
    1,165

    Default

    Quote Originally Posted by 1OLDTIMER View Post
    Good data. I find this VERY interesting, especially that 78% involve (some type of) 'driver error', and that 93% occur on 'dry' road surfaces.

    I wonder if this equates to; not paying attention, and not considering the weight/height of the vehile while cornering or exiting on ramps? A less than full tank (like when returning) will overturn easier than a when full.
    I think the real interesting stat is that 66% of rollovers had drivers with more that 10 years experience. I thought that number would be the other way around.

  20. #20
    Forum Member

    Join Date
    Nov 2007
    Posts
    600

    Default

    Quote Originally Posted by johnsb View Post
    I think the real interesting stat is that 66% of rollovers had drivers with more that 10 years experience. I thought that number would be the other way around.
    How about the incidental 56% that occur on straight roads? Over half. That one got me.

    My understanding is that that, predominately, the right front wheel left pavement and drivers over-corrected when returning to the pavement. You should come back on in an oblique angle regardless of the damage to your tires as they scrub on the side. To be honest, I just couldn't read the whole report so they might have reached different conclusions at the very end.

  21. #21
    Forum Member

    Join Date
    Feb 2012
    Posts
    85

    Default

    In the video the chauffeur was to blame. He tried to make a turn with a vehicle in the way. Speed is the biggest reason trucks,engines,tenders get into accidents.

  22. #22
    Forum Member

    Join Date
    Nov 2007
    Posts
    600

    Default

    Quote Originally Posted by SuperFire123 View Post
    In the video the chauffeur was to blame. He tried to make a turn with a vehicle in the way. Speed is the biggest reason trucks,engines,tenders get into accidents.
    Complacency would get my vote.

  23. #23
    Forum Member
    1OLDTIMER's Avatar
    Join Date
    May 2008
    Location
    USAF 389th SAC
    Posts
    255

    Default

    My understanding is that that, predominately, the right front wheel left pavement and drivers over-corrected when returning to the pavement.
    I have to agree, especially where 'tankers' are (mostly) in use...on narrow, two-lane country roads that do not have hydrants, otherwise why would you need a tanker. Another 'issue' is (not pertaining to rollovers), crashing through 'light' bridges in rural areas. There are many out there, and some are 'reduced' especially during the spring season.

    "the apparatus will not do the folks waiting on it any good, rolled over or involved in a crash"
    "we will bankrupt ourselves in the vain attempt at absolute security"
    Pres. / General Dwight D. Eisenhower

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Pumper/Tanker vs. Tanker Funding Question
    By KOA74 in forum Federal FIRE ACT Grants & Funding
    Replies: 10
    Last Post: 08-14-2011, 09:43 PM
  2. Roll out
    By nicolemcgrgr50 in forum Firefighters Forum
    Replies: 0
    Last Post: 02-18-2009, 12:43 PM
  3. Crimson Tanker vs Rosenbauer/Central States Tanker
    By mtzionc2 in forum Apparatus Innovation
    Replies: 28
    Last Post: 12-27-2007, 05:05 PM
  4. What should roll first? Why?
    By Resq14 in forum Fireground Tactics
    Replies: 19
    Last Post: 07-31-2004, 01:14 AM
  5. used tanker/pumper tanker
    By sklump in forum Volunteer Forum
    Replies: 10
    Last Post: 06-02-2004, 07:49 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Log in

Click here to log in or register