>> whom to the department of building inspection brown bag lunch. this is part of our ongoing series, third thursday of every month. one of the few walking tours we're doing this year. today we're going to talk about high rise buildings in san francisco. we're going to look at just a couple of them. to talk from an angle that most people don't usually see which is smied the buildin inside the.

>> with everything stripped off, all the sheetrock, and the ceiling. you get to see the bones of the building. >> and the ventilation and the fire protection. so this is a really unique opportunity. should be a lot of fun. feel free ask questions as we go. we'll here with path buscovich, engineer, engineer for many of the high rise owners in san francisco. we have other snerkts from the e department of building inspection. we're going to start right now by walking down into the concourse lower level and take the freight elevator up. so come on with us, okay? [ ♪music ] >> okay. we are up here in one of san francisco's major high rise

buildings, one of the tallest buildings. not the tallest but one of the tallest. >> the tallest occupied floor building in san francisco. >> everybody has a slice of really soon. actually the tallest building is the transamerica pyramid building. you could say it's the sutro tower, transamerica pyramid is the tallest building. we're here and we have the unique opportunity thanks to the building owners and the managers of the building to come in and take a look at how the building is made and ough all of its mechanical systems. what keeps a mooirj major high rise building -- how many stories is this building? >> 50 stories, plus or minus a few. it was designed in the '60s by the firm buneir, who are the preeminent structural engineers from 1925 until this building.

and then after this building they were priced out of the market by architectural firms that gave away the engineering services. the form of brunier was about 30 years ahead of their time. their designs are brilliant. and if you look at buildings that they did in the '20s and '30s it was like this guy was so smart, it was mind-boggling. >> so this building is a high rise building and a high rise building is one which is more than 75 feet from the ground, from the sidewalk to the highest occupiable floor. >> which is generally seven stories. >> typically more than seven story buildings become high rise buildings. and in san francisco, there are about 500 high rise buildings. we are requiring the fire pring lers be added to all -- sprinklers be added to all high

rise buildings except for certain residential uses only. >> and historic. >> historic buildings, now sprinklers are required in essentially all high rise buildings. so this is to pick up the ones that were built up to that period. >> one of the important things about the nuances of sprinkler systems. sprinklers are not intended to put out the fire. the sprik ler -- sprinklers are intended to keep the fire install enough for the firefighters to put the fire out. >> the high rise buildings able to be built, the thing that loud them to be built, you all know what that was, i hope. >> which was? >> 150 years ago, otis designed the first operating elevator with safety features so if the rope or cable broke wouldn't fall 14 floors. and that was in 1854. we just had the -- we all

celebrated wildly the 150th anniversary of otis's invention of the elevator. and it was with that that we then could combine new methods of construction, steel construction and other construction, to build high rise buildings. >> because after about six floors you got kind of tired of walking to your office. there was an upper limit of how tall you could build the building, and get people to walk up to the top and rent space. >> there are super-tall buildings, how fast could you make an elevator accelerate and decelerate and make people comfortable. i'm lawrence cornfield, chief building inspector. the building code is very interesting, it addresses things beyond the structure of the building and the steel and the floor. it addresses things that make

people comfortable. so how fast the elevator goes is the sort of thing that the building code addresses that are sort of social issues. for example, mod yuls of elasticity of flor. you want to stiffen the floor so you don't feel uncomfortable. >> one thing you don't want to have happen, you're sitting at a desk and someone is walk down the hallway. if a floor wasn't designed correctly, your body would actually perceive the vibration and it will be annoying to you. so there is design criteria not just for strength but for vibration control of something called foot fault. >> it all comes down to sort of the nonsafety nonstructural elements which are people being comfortable and in high-rise buildings that has a woal lot of factors. it includes elevator speed, includes how much a building can

sway. >> includes the air. keeping a building cool in the summer and warm in the winter. because all of these windows, none of these are april rabble windows. this building is a completely contained structure. that is the design of all modern high rise buildings. >> let's get back to the building. now we can build since the 1850s a high rise building. and most of them are built to steel frame. >> the building code basically said after a certain height which was 65 feet, you had to go to a steel-frame building. and that code has been in fact since the -- in effect since the '20s. once you went above a certain height you had to go to steel frame. if you looked, even in the '06 quake, steel-framed buildings, almost everyone i know except 1 in the '06 quake went through the quake just fine except one

that had a lot of damage. it's interesting, the structural steel institute did a survey of san francisco after the '06 earthquake, that happened was the only building they omitted in their report. >> the williams building which actually had -- >> a lot of damage. all the other buildings went through fine. >> the steel frame is comprised of a number of different parts. >> there is a square box column here. and underneath this box column is fire proofing. it is not asbestos fire proofing. you don't have to worry about the asbestos. this is a nonasbestos fire proofing. it's got this much fire proof coating, so that for four hours, you could have a fire here, and the steel column would be protected. and the code regulates, that this is four hours, the girders that frame into this are three

hours. the beams that frame into the girders are two hours, and the floors must be two hours. and that tells you how much, how long a fire can burn before there can be a problem. >> right. so this is sprayed on, onto this field. underneath this blueish fire protection, there is a structural steel column here. >> huge. >> huge. it is holding up another 30-some floors above it. >> steel woen won't burn. >> so why do you need fire protection? that's a good question. >> what happens is around a thousand degrees fahrenheit which is somewhere the level of burn, depending on what kind of combustibles you have in the office, steel softens. and it's not good having a soft steel column. >> steel loses its strength. >> it loses its strength in

fires. so this is to protect that. with the fire suppression system, so that the firemen have four hours to get here here. >> we have a teem column. this stuff is sprayed -- steel column. this stuff is blue, this particular building owner uses blue to show this is noncontaminated fire protection without asbestos. one of the big costs of retrofitting high rise buildings when you have to open it up like this is you have possible asbestos contamination and it's a big area to put the area into containment and to mitigate. >> they paint it blue because they really want to make sure everybody knows, this is not asbestos. >> okay. there's another way to do field fire protection. there's a kind of paint. and it's been used for the last 50 year or more. you can paint on steel, it's quite excessive -- expensive, it

is fire proof paint. you have to protect all of the industrial elements except for those which are only for earthquakes. the presumption is, you're not having an earthquake at the same time there is a fire in the building. >> income, you could have an erik and a fire. >> and then an after-shock. all the elements have to be fire protected. so we've got the column, the girder. >> if that girder frames into that column right there on that corner, in between the girders are beams, as you can see, these bumps. and then spanning between the beams is a concrete floor with a metal deck. and it got fire proofing on it also. so lots of fire proofing, concrete also doesn't burn. so they're very conscious ever making sure that the basic

structure of this building is not combustible. and so the sprinklers are basically for what the tenant brings in. >> now, you see the big holes up here in the girders. doesn't that weaken the girders when you put giant holes in them? >> some of the holes don't have reinforcing rings. the other holes do. if you go to the original design you'll see all these holes all designed out individually and when they finally do a build-out those holes are there to install these deducts. and -- >> so a lot of times when you go into a building, especially a wood-framed building, they're up there cutting holes in the industrial members. >> in the wrong spot. >> in the wrong spot and the building inspector says, you have to get your building inspector to check these things out. >> every one of them, there are

about 40 sheets showing every one of these beams with every one of these holes in them. some of these deducts have been taken out and when they come back in and put in the heating, ventilating, air conditioning system, they'll put the deducts back in. the air comes into the building, through these deducts, from below, and -- ducts from below and come in to theseth louver system and the air comes in and the air gets sukt out through the ceiling. and they are recirculating the air out of the system at a very high rate. >> one of the requirements of heating and vent lating is that you put fresh air in to mix. you you have to have fresh air. it's very finely tuned how much fresh air and how much -- and the new california energy code standards are very strict as to exactly how you balance it so you don't have to use too much heat or too much cooling power

in these buildings. >> yes. and a libera little bit of a ner too is they can pressure nuance, the building is at a higher pressure than outside. all buildings have little leak points. if they want they can pressurize this building slightly higher than the pressure on the outside such as this air is being pushed out as opposed to the outside air being sucked in. >> and speaking of pressure san diego, one thinpressurization, e stairs, not just an elevator. have you to have stairs in case of an emergency. >> can you see one of them because see that sign? >> right over there, exit sign. one of the things they do in stairs is to provide a protected environment so that people will not be in a smoke filled stair

tower. and you get into the stairway, the doors close which themselves. that's -- by themselves. that's why we don't let people put door stops. can't use door stops. the door closes and the stairway is pressurized. so rather than sucking any smoke in it's actually pushing smoke out of the stairway. >> in this building, the stairs go out past the plaza and down one more level down and then exit out around the perimeter on exit stairs, over on the corner of kearny and pine you'll see the exit stairs. so the exiting of the design of this building was well thought out. >> and an exit is something that takes you to the street. it just doesn't take you to the lobby. an exit has to get you to the public right-of-way. right sergeant? do we have any questions about building structure of a steel-framed blt?

so the question is shouldn't all the fire protection ratings be uniform? >> the general concept is, you want to protect at a higher level, critical elements. the critical element is the column. >> holding the building up? >> holding the building up. that's why it has four hours of protection. i'm hoping that the fire department can get here faster than four hours. >> and the people leave. >> around the people leave, yeah, one of the biggest contents is not protecting the building and contents, but providing the people a sufficient amount of time for evacuation. in san francisco, on rincon hill and south market, under construction right now, we have a high-rise concrete core buildings where the buildings are not made of steel columns, they're made of essentially a

very highly reinforced concrete core, unusual designs that need to be carefully reviewed by the building departments. we have other types of buildings. in fact the building code says you're allowed to build out of any material, and we review it so you can make it out of egg cartons, if you can prove to us properly and annal little cli that the thing could work. of course you couldn't. >> concrete is actually a for example to the rebar. so -- a protection for the rebar. you don't need to put on fire proofing onto the concrete. if you make the concrete thick enough such that the concrete acts as the fire proofer. >> we were thinking about how we could get aw