Equipment (ladder) – where to go? (4)
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This post was last edited by “High-end, classy, and stylish” on April 30, 2014, at 14:57. I had a meeting this morning, which disrupted my schedule; I’m late now. I apologize for making everyone wait so long. Without further ado, let’s get straight to the point – today we’re talking about TI ladders. Issue 4: Placement of ladders. First, let’s talk about the requirements for ladders: These requirements are also specified in 20546, but they relate to fire safety and evacuation purposes. I think that if you have read my previous posts, then for this purpose, these three points are sufficient. 1. Sloping ladders should be used for the main ladders in workshops and structures, as well as for the ladders on platforms that are used frequently. 2. Sloping stairs should be used for the combined platform of towers arranged in groups ； 3. Except in the aforementioned situations, straight ladders should be used. Speaking of the ladder dimensions again: 1. The inclination angle of an inclined ladder should not exceed 45°, while for ladders that are used for frequent two-way traffic, the inclination angle should not be greater than 38°. The height of the ladder should not exceed 5.1 m; if it exceeds 5.1 m, a landing platform should be provided, with the ladder installed in sections. I’d like to share my thoughts on this. Those who have seen 20546 know that the standard angle for an inclined ladder is between 45 and 59 degrees. I designed a ladder with an angle of 55 degrees – it’s easy to climb up but difficult to come down, as it’s very steep. If such a ladder were 5 meters high, people who are afraid of heights would definitely not be able to get down. Therefore, I recommend keeping it below 45 degrees; for those who run back and forth frequently, or those who need to carry items while moving around, it should not exceed 38 degrees. Let me talk a bit more about the height. The standard specified is 5.1 meters, which is based on the building modules used in construction. However, I personally think that working at heights above 3 meters becomes exhausting; especially when workers have to carry heavy loads, they will definitely complain if they have to work without taking a break at such heights. If the specifications for spiral stairs are rather confusing, with requirements of 5m, 6m, and 8m for each section, my personal experience on site and discussions with the workers suggest that a length of no more than 5m per section is the most suitable. 2. The net width of an inclined ladder should be between 0.6 and 1.1 meters. However, note that the width of the area in front of the inclined ladder must be 1.2 meters. When the height difference between the two platforms is 0.3 meters or less, there is no need to install intermediate steps; nevertheless, it is advisable to have a vertical barrier in place. If the height difference exceeds 0.3 meters, intermediate steps must be added, making sure that the structure remains stable. (Just now someone pointed out that the height of the handrails wasn’t specified; the current practice is a bit different from before. Previously, for heights below 20m, the handrail height was set at 1.05m, while it was 1.2m for higher heights. But during one inspection I encountered problems – the building codes require that the handrail height be 1.1m or more for evacuation stairs. As a result, in the designs, the handrail height was set at 1.1m for heights below 20m, and 1.2m for heights above 20m.) 3. The clear width of a straight staircase should be between 0.4 and 0.7m; ideally, if conditions permit, 600mm would be the best choice. With a staircase that’s only 0.4m wide, it’s difficult for someone with a fuller build to get through – every time I lift my legs, the railing brushes against my buttocks, and it’s hard to switch arms while using the staircase. Also, it’s inconvenient to step on the stairs with both feet together. Therefore, it is best to make it larger if possible; 600mm is the most suitable size. 4. Straight ladders with a height of more than 3 m should be equipped with safety guards; the lower end of these guards should be at least 2.2 m above the ground or platform surface, and they should be at the same height as the railings. The value I provided might be lower than what is specified in the standards; some standards require a height of over 4 meters. I believe that a height of 4 meters is enough to cause injury, so I chose 3 meters. Safety first. 5. Except for chimneys, straight ladders should lead from the side of the equipment to the platform (in the case of manholes); those with a length of more than 10 meters should be divided into sections. The ladder sections should be arranged horizontally in an interlaced pattern, with platforms provided between them. The ladder spacing can be reduced as needed. 6. When used as an evacuation staircase, the height of each flight of stairs in a straight staircase should not exceed 15 m. 7. Automatic or manual safety barriers should be installed at the entrances and exits of all vertical elevators on platforms; this is because while barriers are present in other areas, they are not available at the elevators, which increases the risk of people losing control and falling down the ladder inside the elevator shaft. What was mentioned above is from the perspective of ladders alone; for information related to fire safety and evacuation, please refer to my previous post on building codes & petrochemical regulations – go to my space to find that initial series. I won’t say more here, or else there won’t be enough space. Below are photos of an inclined ladder and a straight ladder. The site is quite messy as work is currently in progress; please understand. If anyone has good photos or photos that show any issues, please share them so we can all discuss them together. Starting from the next issue, we will discuss equipment layout in detail by type of equipment. ---------------------------------------I am a divider line------------------------------------- Where to go with the device? (1) http://bbs.hcbbs.com/thread-1286874-1-1.html Where are the devices going? (2) http://bbs.hcbbs.com/thread-1287989-1-1.html Where are the devices going? (3) http://bbs.hcbbs.com/thread-1288786-1-1.html For more interesting content, please visit my space{:1_90:}{:1_90:}{:1_90:} http://bbs.hcbbs.com/home.php?mod=space&uid=891276 I will share each update with my audience; feel free to engage in discussions, ask questions, and provide feedback.
This post was last edited by manman2000 on 2014-4-11 at 11:07. Finally it’s here; I even managed to get a sofa. I’ll go back and take a look later
This post was last edited by manman2000 on 2014-4-11 at 11:20. I have a question: is it necessary to have a handrail at the very top of a straight ladder? The guardrails for platforms at a height of 20 meters above the ground need to be 1.2 meters high. If there is a smaller platform on top of a larger one, and both are at 20 meters above the ground but only a few meters apart, do the guardrails on the smaller platform still need to be 1.2 meters high? In that case, anything that falls will land on the larger platform
Ladders that are too steep make it difficult to go up and down; especially in cases of escaping an accident, there’s a risk of falling down from them. If they are too long, it’s hard to lift heavy objects while using them to go up or down. Narrow steps make it hard to stand steadily, and one isn’t a person with tiny feet anyway
The angle of the ladder is very important, especially for platforms that are used frequently. I’ve experienced it firsthand: it’s a sloping ladder with an angle of around 60 degrees, and it’s quite difficult to climb up it. Especially since we also have to carry medicines up there, which makes things even harder. The ladder is only wide enough for one person to walk on, so every time I carry something up, I curse the designers for making such a terrible ladder – it’s exhausting! :@ So the designers really need to consider the needs of those who use this ladder: lol
It’s tall. I have a question: when the ladder on the spherical tank intersects with the fire hoses, how is that handled? Which one goes around the other, or do they just intersect? I found a picture online; it’s not very convenient for the worker to move up and down, especially when carrying tools
The last edit to this post was made by swwsdwf on 2014-4-11 at 12:29. Bring a stool; those who haven’t come, raise your hands. Let me count: Well, there’s no railing of the right height; Teacher Gao, please call him over quickly
There’s something new to learn this weekend* again
The stair treads in the picture are quite good.
These steep, narrow ladders are the most prone to accidents; people have fallen down them.
I have a question: “The width of the area in front of the inclined ladder should be 1.2m” – does this mean that there should be at least 1.2m of space in front of it once one climbs up the ladder?