Spiral: From the Book of Saw topped the domestic box office by default this weekend, with a slightly underwhelming (even on a Covid-curve) $8.725 million. Yes, the R-rated, $20 million Saw sequel/revamp might have opened much closer to Saw 3-D ($24.23 million in 2010) than Hostel 2 ($8.2 million in 2007) sans Covid-specific complications. The film would be boasting a mix of old (Darren Lynn Bousman returning after directing Saw II, Saw III and Saw IV) and the new (Chris Rock and Samuel L. Jackson dealing with a Jigsaw copycat sans many ties to the previous eight movies) opening in a flashy pre-Memorial Day weekend frame (May 15, 2020) just as John Wick: Chapter 3 had scored a year prior. Armed with good (for a Saw sequel) reviews, generational nostalgia for the franchise and flashy marketing, Spiral may have been the jolt the Saw franchise needed.
Well never know what could have been, but thats the optimistic scenario. The equally likely pessimistic scenario, one that may be closer to this What if, is that audiences who jumped ship after the small-scale and underwhelming Saw V in 2008 (just in time to ignore the franchise-best Saw VI in 2009) werent coming back. The franchise was a defining horror relic of the post-9/11 era, but it came and went a decade ago and peaked back when John Boehner was still Speaker of the House. Yes, horror junkies (and critics of a certain taste and culture) appreciated the series not so much for its gross-out traps and extreme gore but for its hilariously convoluted soap opera continuity, an interconnected timeline that would precede the MCU and the modern Fast & Furious saga. But maybe regular audiences were no more nostalgic for Saw than they were for Terminator.
Its possible that Saw fell into a Terminator Trap (a term I am just now coining). Thats when a desperate-to-survive franchise tosses off two lousy installments (Salvation and Genisys) and burns both general audiences and fans, only for both to stay home when we get a halfway decent revamp (Dark Fate). Saw 3-D and Jigsaw are (arguably) the two worst entries in the long-running Saw saga, while Spiral is among the better ones. My hooked on true crime docs 13-year-old daughter thinks its by far the best Saw ever put that in an ad!. Yet, if youre a fan burned by Saw: The Final Chapter and Jigsaw (a giant nothing burger of a soft reboot/sequel released in 2017), you might not be racing to theaters to see if the third time was the charm. This might help explain why Spiral couldnt crack $10 million even on a Covid-curve.
Again, the pandemic and its related challenges (40% of theaters closed, all theaters dealing with limits on capacity and operating hours, etc.) played a role this weekend. But a 40% fresh from Rotten Tomatoes (just above the 39% for Saw VI), B- from Cinemascore (the scores have ranged from a C for Saw V to a B+ for Saw II), and a 2.35x weekend multiplier (normal for Saw sequels) suggests that Spiral is playing like a Saw movie, which means the low opening weekend wont be mitigated by longer Covid-curve legs. Wrath of Man dropped a normal 59% this weekend after a normal for Jason Statham $8.1 million debut, while Mortal Kombat opened with a solid-for-Covid $23.3 million and sank like a stone. If it plays like a Saw movie, were looking at a domestic total essentially tied with the openings for Jigsaw ($16.6 million in 2017) and the original Saw ($18.4 million in 2004).
Lionsgate deserves kudos for going first theatrically during what will be a very complicated summer. Spiral might stick around against A Quiet Place part II (May 28) and The Conjuring: The Devil Made Me Do It (June 4) to pull a Wonder Woman 1984-level 2.8x multiplier for a $23.5 million finish. Even Saw VI ($70 million on a $10 million budget), Saw 3-D ($134 million worldwide, including a franchise-best $87 million overseas, on a $17 million budget) and Jigsaw ($104 million/$10 million) were profitable. If the folks behind Spiral have a good pitch for Saw X (perhaps in a X-Men: Days of Future Past-like combo featuring the survivors of Spiral and the original Saw flicks), then they can spend $20 million and hope Spiral was a victim of the times. After all, with $994 million global and counting, Saw is still going to crack the $1 billion mark.
I've studied the film industry, both academically and informally, and with an emphasis in box office analysis, for nearly 30 years. I have extensively written about all of said subjects for the last 13 years. My outlets for film criticism, box office commentary, and film-skewing scholarship have included The Huffington Post, Salon, and Film Threat. Follow me at @ScottMendelson and "like" The Ticket Booth on Facebook.
I've studied the film industry, both academically and informally, and with an emphasis in box office analysis, for nearly 30 years. I have extensively written about all of said subjects for the last 13 years. My outlets for film criticism, box office commentary, and film-skewing scholarship have included The Huffington Post, Salon, and Film Threat. Follow me at @ScottMendelson and "like" The Ticket Booth on Facebook.
A criminal mastermind unleashes a twisted form of justice in Spiral, the terrifying new chapter from the book of Saw.A criminal mastermind unleashes a twisted form of justice in Spiral, the terrifying new chapter from the book of Saw.A criminal mastermind unleashes a twisted form of justice in Spiral, the terrifying new chapter from the book of Saw.
Be holiday-ready when you learn how to cook a ham like a pro. Whether you're a beginner or cooking ham number 354 (if you kept track), we've got step-by-step instructions for cooking a ham in the oven, plus information about the different types of ham. Get ready to make this year's holiday meal the best ever.
A gorgeous baked ham is the best centerpiece we can think of for holiday meals. It looks impressive (especially with a glistening ham glaze), but takes very little work to get on the table. Luckily, there are many ways to cook a ham. You can bake ham, grill it, even cook it in a slow cooker! So even if your oven is full of holiday sides or pies, youve got other appliance options. We'll tell you how to cook ham all those ways, plus offer tips on carving and how to choose a ham when you're at the grocery store.
When it comes to learning how to bake ham there are only a couple of stepsprep the ham and bake it! It's pretty low-fuss since most hams available at the grocery store are already cooked. Follow these instructions for tender, perfectly cooked ham.
Preheat the oven to 325F. You don't need to wash a ham before baking. If you ask us, baked ham is delicious even when you leave it plain; however, scoring a diamond pattern with a chef's knife in the outer layer and brushing on a glaze during baking makes the ham a showy centerpiece and adds flavor. Use your chef's knife ($90, Sur la Table) to make diagonal cuts about 1 inch apart on the ham. Cut through the surface of the ham so the glaze penetrates the ham. If desired, insert whole cloves ($5, Target) into the ham for decoration and flavor. It's easier to poke them in where the cuts intersect. (Remove the cloves before eating the ham.)
Place the ham on a rack in a shallow roasting pan ($53, Bed Bath & Beyond). Insert an oven-safe thermometer into the center of the ham. (It should not touch the bone of a bone-in ham.) Bake, uncovered, in the preheated oven until ham registers the desired temperature (140F for pre-cooked ham). Because cooking times vary based on the size and type of ham, use the timings below as a guide.
If you're using a glaze, the best time to put it on is during the last 15 to 20 minutes of baking time. If you glaze the ham sooner, the sugar in the glaze may cause it to burn. Pull the oven rack out, and use a basting brush ($11, Target) or spoon to cover the ham with glaze. Continue baking. Reserve any remaining glaze to serve with the ham.
Cooking ham for the holidays is pretty darn easy. If you're looking for an oven-baked recipe, this basic holiday ham is a great place to start. This recipe teaches you how to glaze a ham and includes three different glaze recipes.
Yes, you can make slow cooker ham. For a 5- to 6-quart slow cooker ($90, Bed Bath & Beyond), choose a boneless ham that's about 5 pounds, brush it with a glaze, and slow cook it, covered, for 8 to 9 hours on low-heat setting. Get step-by-step directions for our Cherry Cola Ham recipe in the slow cooker.
Insert a meat thermometer in the thickest part of a cooked ham shank. For a charcoal or gas grill, cook indirectly by arranging medium coals around a drip pan. Test for medium-low heat above the pan. Place the ham on the grill rack over the pan, cover, and grill until ham reaches 140F (timing guidelines below), brushing ham with desired glaze once or twice during the last 20 minutes of cooking. Cover with foil and let stand for 15 minutes before carving. (The temperature will rise 5F during this time.)
Preheat your oven to 325F. Line a shallow roasting pan with foil. Between the slices of one 8- to 10-pound spiral-sliced ham insert half a thinly sliced orange; four garlic cloves, slivered; and sprigs of fresh rosemary and/or thyme all the way around the ham. Transfer ham flat side down to the prepared pan. Cover with foil. Bake 2 to 2 hours or until browned and heated through (140F). For the last 45 minutes of cooking, uncover and spoon glaze over ham (if you're using a glaze). Transfer to a platter using two large, wide spatulas.
When you don't need to cook a full ham, ham steaks are a good option. Lightly coat a heavy skillet ($110, Target) with nonstick cooking spray or use a nonstick skillet. Preheat over medium-high heat until very hot. Add ham steak, and reduce heat to medium. Cook, uncovered, for 9 to 11 minutes (for a -inch thick steak) or until heated through (140F). Ham steaks are ideal for grilling and broiling too.
Place the ham on its flattest side. If there isn't a flat side, use acarving knife toslice off a small piece of ham from the bottom so the ham will sit flat. Cut slices down to the bone, thencut along the bone to release the slices.
Bone-in: At least part of the leg or hip bone is still in place, which adds flavor during cooking. You can purchase a fully cooked whole ham, which includes the entire cured leg, but the rump half (round, meatier end) or the shank portion (tapered and easier to carve) is usually enough for most occasions (a 5- to 6-pound ham makes 16 to 20 servings). The rump half is usually meatier and more tender than the shank half, which is usually slightly tougher and has more connective tissue.
Boneless: All of the bones have been removed. The shape of the fully cooked ham is reformed, and the ham is wrapped or canned to hold the meat together. Some canned hams are formed from pieces of ham held together with a gelatin. Boneless hams are simple to slice.
Natural-uncured:Hams with this label are usually preserved using celery powder, which is organically rich in nitrates, then smoked. Labels that include "ham with natural juices" don't have much added water and could take up to 60 minutes longer to bake.
When purchasing a cooked, cured ham, choose one that is firm and plump with rosy-pink meat. For a bone-in ham, such as a rump half or shank portion, figure about three entre servings per pound. For a boneless ham, plan on four to five servings per pound. Unless the label says otherwise, assume your ham needs to be refrigerated. A boneless, uncanned ham can be refrigerated for up to one week; shank and rump portions can be refrigerated for up to 2 weeks.
That has been my past experience with spiral sliced hams. Every time I have had one cooked for me I have not enjoyed it. The spiral hams of my youth were all dry and stringy. This has kept me from buying one myself.
The reason why anyone buys a spiral ham is that it is easier to carve, since it has been pre-sliced. The problem with that is it makes it easier for the meat to dry out. Juices can easily run of the meat and into the pan. This is the price for that convenience.
Another issue contributing to dry ham is that it is overcooked. Nearly all hams come already cooked, so it's really just about re-heating and if you are applying a glaze, cooking the glaze so it sticks to the meat.
The first and most important thing to do is take the ham's temperature using either a probe thermometer that stays in the meat while it's in the oven and check using an instant read. A probe would be the easiest.
If you don't have a probe thermometer use the time guide that came with the ham, but it wouldn't be nearly as accurate. Those guides can't take into account all the other variables - like size and shape of meat, actual temperature of your oven, how clean your oven is (burned up junk in your oven can affect the cooking time).
If you are using a probe thermometer, place it in the deepest part of the ham without hitting any bone (the bone will throw off your reading). Then set the alarm to go off at 130 degrees if applying a glaze, otherwise let your ham go to 140 degrees.
Yes, I know that sounds low, but trust me on this. It took my 8-pound ham about 4 hours to cook. If you just can't wait that long you can raise the temperature but I highly recommend you do not go any higher than 350 degrees.
If you are in the market for a spiral ham, may I suggest Dearborn's Famous Spiral Sliced Ham. Everyone I have talked to about them in Michigan knows who they are and their eyes light up and appetites increase when I mention them. Don't fear, thanks to the internet, you can order one of these delicious hams.
Dearborn has been around for over 70 years- three generations of knowledge of crafting quality meats. They know how to make a good ham. The last time we cooked one up, my wife and kids starting devouring slices the minute I was done taking photos.
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I would like to know how to keep the ham from drying out once you place it on the dinner table to eat. I put juice from a beef roast on the platter to keep sliced beef roast from drying out, but what would you suggest with ham?
That's why I don't like spiral ham as much as you are finding it's not easy to keep moist. You need to cook it on a low temperature and keep it well covered. But if you keep end up in frustration, I would skip the spiral sliced ham and buy one that isn't pre-sliced and learn how to carve it.
Just a tip I've always done and never made a spiral ham that dried out. I baste it every 10 or minutes, just like I do with a Turkey. Always moist. I also keep it covered on the table and serve the juice in a gravy boat. So you can keep it moist on your plate. Always a big hit
You might recognize the two symbols above. The one on the left is used to denote that a duct will be round. The one on the right denotes that a duct will be flat oval. Most of the time, for a typical HVAC system, they indicate you want spiral duct.
But for some reason, we often see engineers leaving these symbols off of their drawings. Perhaps they cant find them in their CAD libraries. But when you leave them off, you are usually going to end up with poor-performing and costly rectangular duct.
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1. You wont follow the ASHRAE Advanced Energy Design Guides its a big deal to try and reduce energy use in commercial buildings by 30% and 50%. And ASHRAE has worked extensively to help its members achieve these goals by compiling research and assembling cost feedback that might be impractical for a single engineering firm to do. The Advanced Energy Design Guides were written by your fellow engineers, not a trade organization or some contractor that bought a coil line and needs to get the most use from it. They specifically state Round duct is preferred over rectangular duct. However, space (height) restrictions may require flat oval ductwork to achieve the low-turbulence qualities of round ductwork.
2. Youre going to get more turbulence, and turbulence is bad you dont even have to be an engineer to know those square corners of rectangular ductwork cause far more turbulence than no corners (round) or rounded corners (flat oval). We all kind of know without trying it that putting a rectangular drain line downstream of your toilet would pretty much assure regular visits from the plumber. Things just dont flow as well when you have square corners. And with airflow, that gives you two unwanted problems that are directly related to turbulence higher pressure drops and increased noise.
3. Youre going to need more duct the only reasonable way to decrease pressure loss and noise in a duct (other than change its shape which we are trying to get you to do) is to slow the air down. Yes, you need to make the duct bigger. For aspect ratios 2:1 to 4:1 pretty typical for rectangular ducts the perimeter relative to an equivalent round diameter is 30 to 55% (2013 ASHRAE Handbook Fundamentals, Chapter 21 Duct Design, page 12, about midway down the right side of the page). Were not making this up! And its pretty easy for you to confirm after a couple of moments on your Ductulator.
4. Your ducts going to weigh a lot more, and need a whole lot more hardware screwed/welded to it youve probably heard or used the term built in accordance with SMACNA. Thats most often referring to the 2005 SMACNA HVAC Duct Construction Standards Metal and Flexible. It is an excellent structural standard thats mostly showing you one thing how to limit deflection. Whether dealing with how much an assembled length of duct deflects (hanger spacing and seismic bracing) or how much the walls of a duct deflect (limiting metal fatigue, low-frequency noise generation and how the duct may impede other items within the building), the goal is to keep a duct system as static and motionless as possible. Flat surfaces deflect. Round/curved surfaces have little-to-no deflection in positive and low pressures. The SMACNA manual will have you increase the gauges or add reinforcing to limit deflection. So not only do you have to increase the amount of duct (perimeter) to reduce pressure loss and noise, you also have to increase the weight of that perimeter to reduce deflection.
5. Your ducts going to cost a lot more the cost of ductwork, both to buy/make it and to install it, has a direct correlation to weight. Keep in mind the chart above. Even if someone says their cost per pound is less for rectangular duct, thats quickly negated because it takes a lot more pounds of rectangular duct to carry the same amount of air. Installation labor skews even more in favor of round duct. Weight-based labor formulas generally allow 50% more pounds per man-hour for installing round and flat oval spiral duct versus rectangular. So if you pick an example from the chart above where rectangular duct weighs 50% more than spiral round duct, it only takes 44% of the labor to install the spiral round duct compared to the rectangular.
8. Your duct is going to leak twice as much rectangular duct constructed to Seal Class A (transverse and longitudinal seams sealed, openings for rotating shafts sealed) are expected to leak 6 cfm/100 ft2 duct surface area at 1 WG. Round and flat oval spiral ducts constructed to Seal Class A are expected to leak 3 cfm/100 ft2 duct surface area at 1" WG.
9. Youre going to have a hard time meeting the ASHRAE Standard 90.1-2013 Energy Code it states Ductwork and all plenums with pressure class ratings shall be constructed to Seal Class A, as required to meet the requirements of Section 220.127.116.11.2 (the Duct Leakage Class). It doesnt say you have to test it, but you are expected to meet the same standards as the duct you are required to test. That Duct Leakage Class is 4 cfm/100 ft2 at 1 WC. Rectangular duct meeting the required Seal Class A is expected to leak 50% more than the allowance. Round and flat oval spiral duct is expected to leak only 75% of the allowance. Perhaps we should pause a moment to let these numbers sink in. If more than 33% of your total square footage of ductwork high pressure, low pressure, medium pressure, return air and exhaust is rectangular duct, even constructed to Seal Class A, instead of round and flat oval spiral duct, you are designed to fail!
10. Youre going to need a lot more duct sealant even if you dont test the duct to find that youve failed the energy code, youre still required to construct the duct to Seal Class A. When you do that, youll get a pretty good picture of why rectangular duct leaks at least twice as much as spiral duct. First of all, you have to seal the longitudinal seams of the rectangular duct. You dont have to seal the spiral lockseams of the spiral ducts. That is specifically stated in the ASHRAE standard, and testing has confirmed that spiral seam leakage is negligible between a Duct Leakage Class of 0.02 and 0.3. Most leakage for all ducts occurs at the joints, and you are going to have about twice as many duct joints to make with rectangular duct (standard 56 lengths from a TDC coil line) versus spiral duct (commonly supplied in 10-0 lengths). That by itself should give you an expectation of twice the leakage. And within the rectangular joint, the biggest culprits are those pesky corners the same ones that cause the turbulence that gives rectangular duct its higher pressure drops and increased noise. Lets pick an example from our chart above 18 versus its equivalent rectangular size of 24 x 12.
Example #2100 lineal feet of 24 x 12 rectangular duct100 ft x 12 in/ft x 2 longitudinal seams = 2,400 lin.in. of longitudinal joint sealing100 feet / 56 in/section = 21.43 sections = 21 joints21 joints x 72 perimeter inches = 1,512 lin.in. of joint sealingTotal = 3,912 lineal inches of longitudinal and joint sealing
11. Youre not going to have an easier time fitting the duct into the allotted space there seems to be this mistaken idea that if ceiling space is tight or congested, your solution is to use rectangular duct. First of all, flat oval duct is going to work anywhere rectangular would, but without the pressure drops, noise, leakage and weight. Second, anyone thats ever seen a bad contractor snake a 25-0 length of flex duct through an attic and we really recommend that you dont allow that should understand the concept that a round duct can be maneuvered more readily than rectangular duct without compressing the area. And with slip-joint construction you trim duct lengths of round and flat oval spiral ducts without compromising their integrity or performance. Have you ever looked at rectangular duct thats been field adjusted? Its usually not very pretty. In any case, you shouldnt base the design of a commercial duct system on the premise that what you draw probably wont fit, so you need to plan for the contractor to have to change everything in the field. If thats the case, please make a big note on the plans so we know to avoid that project.
12. The duct wont be easier or faster to get this one really doesnt make sense for commercial construction, yet we hear it all the time. Yes, many sheet metal contractors have their own shops and could in theory go out there and make the duct for your project right now. In the real world, they try to keep their shops busy and your job will wait in line. If their shop is not busy, their cost to make rectangular duct will be much higher. If you really need the duct fast, there are dozens of places within a one-day shipping frame of your jobsite where you can find spiral round duct and fittings in stock for immediate shipment in the size range you should need on a fast-track project. Most commercial duct projects go through months of coordination and detailing, so getting any duct regardless of what you think shop lead time is is a matter of planning, not availability. And round and flat oval spiral duct are neither hard to find or noncompetitive. We really hate to plug our competition, but within a 600-mile radius of our plant in Ft. Worth, Texas you can find more than 100 spiral duct machines and at least 15 ovalizers. No, availability is not an issue
Do you see where were going with all this? The numbers stack up overwhelmingly in favor of round and flat oval spiral ducts. The ASHRAE Handbooks and Design Guides tell you to use round and flat oval ducts over rectangular ducts. ASHRAE research projects prove better performance from round and flat oval ducts. Other testing projects from manufacturers, trade groups and government organizations like the Department of Energy support the advantages of round and flat oval duct over rectangular. Countless real-world examples where a contractor or manufacturer converted a mostly rectangular duct design to round and flat oval spiral duct, have proven you can get better performance at a better installed cost.
But if you dont use those symbols above and indicate you want round and flat oval duct for your project, you will almost certainly get rectangular duct. It will not perform as well, it will probably cost more, and you will have done the owner no favors. As obvious as it may be that you should have used round and flat oval duct, the contractor probably needs the rectangular work to pay for his shop and no one has the time to re-design the job and show how the duct system could have been much better.
Spiral round lock-seam duct is the most efficient way to transport air in HVAC systems. The round profile greater flow efficiencies than rectangular ducts. Because round ducts are inherently stronger than rectangular profiles, they can be lighter metal gauges and can be installed in longer spans. The 4-ply spiral lock-seams of spiral duct create a product that is stronger than traditional welded-seam round ducts of the same gauge. Spiral lock-seams have practically no leakage, and are the only mechanical seams exempted from sealing under energy standards such as ASHRAE Standard 90.1-2013.
At Spiral Pipe of Texas, we make products that meet or exceed the SMACNA HVAC Duct Construction Standards Metal and Flexible (2005). We make diameters ranging from 3 to 92 and metal thicknesses from 26 gauge to 16 gauge. The following is our construction standard for positive pressures to +10 WG.
Galvanized Steel G60 and G90 Mill Phosphatized Steel (Paint Grip) Galvanealed Steel A60f Stainless Steel 304L and 316L 3003 Aluminum SPOT Agion (anti-microbial coating) Polyvinyl Coated (PCD) Black Iron
Most HVAC ducts need to be insulated. At Spiral Pipe of Texas, our home area of the Central and Southern US encompasses regions with high fluctuations in both temperature and humidity. So, its no surprise that we have been at the forefront of developing and implementing insulated duct products. Factory-insulated duct products reduce field labor, as well as giving consistency and product features you wont get with thermal wrap. Duct insulation is also critical in reducing HVAC system noise. Here are some of the product options for round insulated duct that are available from Spiral Pipe of Texas.
Double-wall construction allows you to contain the insulation media between an inner and outer metal shell. The insulation is protected from external damage a critical concern for ductwork on rooftops and out of the building envelope. Where ducts are exposed to view, insulation is concealed for a more pleasing appearance.
The internal metal shell gives protection from insulation erosion, maintains a smooth duct cross-section, and makes cleaning the ducts easier. There are quite a few options available for double-wall ducts, so its important that critical features are specified. Here are some of them.
For HVAC air ducts, the outer shell is the structural and pressure containment portion of the product, and is the basis of construction. Unless noted otherwise, double-wall ducts are fabricated in accordance with Chapter 8 of the SMACNA HVAC Duct Construction Standards Metal and Flexible (Third Edition 2005) and the outer shells are constructed in accordance with Chapter 3 of the same standard.
It is important to note that the dynamic airflow performance of a duct system is based on the inner shell, and most duct sizing on mechanical drawings are I.D. Yet, it is the outer shell that determines gauge, reinforcing and construction, as well as defining how a duct fits within the physical constraints of a building. Fitting dimensions (elbow centerline radii, tee fitting length, tap clearance to end, etc.) are based upon the outer shell, not the inner.
Materials G90 and G60 galvanized steels, paint-grip mill phosphatized steel, A-60 galvanealed steel, black iron, aluminized steel, 3003 aluminum, 304-L and 316-L stainless steels, PCD Polyvinyl Coated Duct, Agion anti-microbial steel.
Appearance and finish standard factory finish (no special cleaning, welds spray-painted, mill markings, labels and piece-marks visible), paint-ready (welds not painted, removeable labels), and factory painted. SPOT has additional literature giving more specific details for our architectural duct products.
Note the Mylar film is an excellent erosion and vapor barrier, but its use may affect the acoustical performance of a double-wall duct, as well altering the flame spread and smoke development numbers.
Standard Material our standard product is a 0.75# density Knauf AtmosphereTM Duct Wrap with ECOSE Technology. The insulation is thicker than the intended annular space between metal shells (1.5 thick for 1 nominal spacing) so that net density is after fabrication is approximately 1.00#. This material is a highly resilient inorganic glass mineral wool with bio-based binders. It does not contain phenol, formaldehyde, acrylics or artificial colors. It carries a GREENGUARD Gold Certification.
Thickness standard 1 and 2 annular spacing. Other thicknesses available. Installed R-Value R=4.2 for 1 spacing, R=8.4 for 2 spacing Surface Burning Characteristics Flame Spread 25 and Smoke Developed 50 (tested in accordance with UL 723, ASTM E 84 and NFPA 255. Temperature Range up to 350F Mold Growth no growth (ASTM C 1338) Note metal spacers are not used to maintain concentricity between inner and outer shells. Though sometimes specified, they make duct assembly with slip-fit transverse joints more difficult, create thermal bridges between the interior and exterior of the duct, and have a negligible effect on actual R-value. In actual practice, insulation compression is more of a concern for larger diameters of duct where double-wall flanges are typically used for transverse connectors, eliminating any need for spacers.
Alternative Material Armacell AP/Coilflex elastomeric foam duct liner. Fiber-free, non-particulating foam alternative to glass fiber insulations. Standard 1 thickness (larger annular thicknesses obtained by wrapping successive layers) with R-value R=4.2. Flame spread/smoke developed index of 25/50 (ASTM E 84) and temperature use limit up to 180F. GREENGUARD Gold Certified. Made with EPA registered Microban antimicrobial product protection.
Spiral Pipe of Texas has been a pioneer in the use of Johns Manville Spiracoustic Plus round duct liner system, providing some of the largest systems ever produced with outer shell diameters up to 92. Like our double-wall products, the outer metal shell is the basis of construction. The Spiracoustic Plus liner has factory-made, evenly spaced kerfs that, when inserted into the outer metal shell, allow it to evenly conform to the inside of the duct.
The product is a high-density fiber glass board with a factory-applied black acrylic coating applied to the surface and transverse edges, JMs Permacoat. After the liner is assembled into the outer metal shell, SPOT provides the finishing touches by using JMs SuperSeal coating product to dress up any exposed edges, as well as utilizing mechanical fasteners as needed to assure the liner stays permanently affixed.
Spiral Pipe of Texas single-wall insulated duct with Spiracoustic Plus liner may have some advantages for your project over traditional double-wall insulated products. With no metal inner shell, the product is lighter in weight as much as 30% lighter in many sizes. Labor needed for transverse joint assembly can also be reduced since a single slip joint is all that is necessary. The product is ideally suited for systems with long, straight runs of duct gymnasiums, cafeterias, airports, sports arenas and convention centers.
Available Insulation Thicknesses 1, 1 and 2 R-Value (tested in accordance with ASTM C518) 1 (R=4.3), 1 (R=6.4), 2 (R=8.4) Diameters Available (i.d.) 1 (6 to 90), 1 (11 to 89), 2 (14 to 88) Density 4.0 pcf Operating Temperature up to 250F Maximum Air Velocity (ASTM C1071) 6000 fpm Surface Burning Characteristics Flame Spread 25 and Smoke Developed 50 (tested in accordance with UL 723, ASTM E 84 and NFPA 255) Fungi Resistance does not breed or promote (ASTM C1338), no growth (ASTM G21) Bacteria Resistance no growth (ASTM G22)
Of course, a provocative response like that deserves some elaboration. And we are happy to provide it. For the last 20 years it has become fashionable for companies to describe themselves as green, and we see plenty of advertising for construction components festooned with leaves and butterflies. Our term for this is green-washing. To be fair, if you have a product where environmental consciousness was not previously a concern, it is a good idea to find out what is green about your product, try and do better, and reassure consumers that you care. Spiral duct has always been green long before the term came into being.
The spiral duct industry started in Northern Europe at the end of World War II. As economies recovered, new and better buildings were incorporating ventilation and conditioning systems that had been developed during the previous few decades. But they had three problems energy was expensive, raw materials were also expensive and often in short supply, and there was a shortage of skilled labor with so many young men lost in the war. To solve all three problems, spiral ducts were developed. Round is the most efficient shape for transporting air. It has lower pressure drops, saving fan horsepower, and there is less heat gain/loss through the surface than with rectangular shapes.
Round is also the strongest shape for transporting air. You need to limit surface deflection to prevent metal fatigue and duct rumble, and metal thickness and additional reinforcement were the ways of accomplishing this with traditional rectangular ducts. Round ducts have virtually no wall deflection in normal operating conditions, and the helical spiral seams strengthen the duct even more.
As a result, spiral duct systems usually weigh 30% less than equivalent rectangular duct systems less material! Spiral ducts are normally produced in longer lengths than rectangular ducts. Where rectangular duct is normally provided in 4 or 5 foot nominal lengths, the standard for spiral duct is 10 feet with lengths as much as 20 feet commonly provided. So, its no surprise that most estimators predict installation rates of 50% more pounds per man-hour installed for spiral round duct than for rectangular duct. And dont forget that were talking about a product that generally has 30% less pounds to start with.
So, here we have a product spiral duct that uses less energy, less material and less labor than other methods of transporting air. By anyones definition, this is an inherently green product. But lets take this a few steps further. Most spiral duct systems produced at Spiral Pipe of Texas are galvanized steel and, where insulation is required, use fiberglass insulation. Galvanized steel is one of the most recycled materials on the planet. Approximately 70% of all steel and 30% of all zinc consumed are made of recycled material. And at the end of service, virtually 100% of galvanized steel ductwork can be recycled. For our insulated products, our standard for double-wall products is Knauf Friendly-Feel Duct Wrap or an equivalent product.
The Knauf product contains three primary ingredients: 1) sand one of the worlds most abundant and renewable resources; 2) a minimum 50% recycled post-consumer glass content; 3) a new binder technology that reduces binder embodied energy by up to 70% and features bio-based materials rather than non-renewable petroleum-based chemicals traditionally used. They contain no phenol, formaldehyde, acrylics or artificial colors.
So, spiral duct is a green product made from green materials. Lets look further at some of the regulations and compliance standards we work under. Most states, including our home state of Texas, have adopted state-wide energy codes. In Texas, we use the ANSI/ASHRAE/IES Standard 90.12013 Energy Standard for Buildings Except Low-Rise Residential Buildings. It calls for ductwork to be constructed to Seal Class A. Part of the requirement involves the contractor assembling our ducts using sealant, but our duct components themselves meet Seal Class A.
The only mechanical seams that do not have to be sealed under this standard are the spiral lock seams of spiral duct. They have been proven to have almost no inherent leakage. Per this standard, all ducts should be constructed and installed to meet a Duct Leakage Class 4, regardless of whether testing is required or not. According to the ANSI/SMACNA HVAC Air Duct Leakage Test Manual-2011, the expected leakage performance of a round or flat oval spiral duct system, assembled to a Seal Class A, is a Duct Leakage Class 2. Our products greatly outperform the energy codes with only half the leakage that is allowed.
And we take duct leakage seriously, because its considered to be the single largest preventable energy waste in commercial and residential buildings even more of a waste than leaving lights and A/C on when the building is unoccupied. To go further, ASHRAE is producing a series of Advanced Energy Design Guides for commercial construction. These are guides for achieving progressive amounts of energy savings toward a net zero energy building and are available for different building types.
Low-energy use ductwork design involves short, direct and low pressure drop runs. The number of fittings should be minimized and should be designed with the least amount of turbulence produced. Round duct is preferred over rectangular duct. However, space (height) restrictions may require flat oval duct to achieve the low turbulence qualities of round ductwork.
So, we know from ASHRAE and SMACNA that round, flat oval and spiral duct is the way to go for efficiency and low leakage. Additionally, ASHRAE publishes a Duct Fitting Database that includes dynamic efficiency data for all duct and fitting configurations. Using it, you can see the actual performance efficiencies of round and flat oval spiral ducts and fittings over equivalent rectangular ducts. These lower pressure drops optimize the duct system performance and allow the transport of air at lower fan horsepower. And with less inherent leakage, you wont need to produce as much air to start with.
Which brings us to the question of LEED. Leadership in Energy and Environmental Design (LEED) is one of the most popular green building certification programs used worldwide. It is an important first step in promoting green construction in commercial buildings. In a perfect world (at least for us) the LEED guideline would simply state Use round and flat oval spiral ducts and fittings from Spiral Pipe of Texas and heres your points! Unfortunately, its not that simple. First, many of the green features of our products are not even things you can get LEED credits for. They actually are prerequisites preliminary requirements to get any level of LEED certification.
So, we hope this answers the question Are Your Products Green? Spiral Pipe of Texas is proud to make products that are green throughout their history and origin, in their manufacture, and through their use. We just usually do it without letting our marketing people put leaves and butterflies on our literature and website.
Finally, there is a solution to your rooftop duct system needs that is the right shape, the right material and the right price. We have combined our almost 40 years of quality metal duct fabrication with a willingness to innovate and explore new technologies. The result is PhenoliDuct. We combine the proven technology of our double-wall duct manufacturing with the properties of Kingspan KoolDuct to give you the perfect rooftop ducting solution.
Rooftop duct should always be round when possible. The round shape sheds rainwater and prevents excessive snow and ice loads. But for most of the country the main reason is wind. A round duct experiences only about 40% of the wind force a comparable rectangular duct would see. Hanger and support spacings are greater for round ducts. And this is truly a round duct, not an 8 or 12-sided adaptation from rectangular duct. Our standard construction uses our spiral duct as the outer shell and a round metal longitudinal-seam duct for the inner shell. Your performance is the same as for our other round duct products.
Our standard product uses the KoolDuct 45mm board. This product has an R-value of 12.0. It is machined to fill a 2 annular space in our double-wall construction, and our process eliminates all potential thermal gaps. This is 50% more thermal performance in a 2 insulation product than you would get with fiberglass or elastomeric insulations.
The KoolDuct board used as our insulation has flame spread and smoke developed indices of 10 when tested per ASTM E84. This greatly out-performs other insulations that struggle and often fail to reach the minimum 25/50 indices required by most codes. We can provide desirable characteristics such as fully-welded fittings without worrying about setting the insulation on fire. Our customers can also perform field-modifications to the duct without creating a fire hazard.
Sheet metal ducts, and particularly spiral ducts, are proven to be durable in outdoor applications. Other rooftop products have been introduced, including some made with phenolic board. Most are simply one or two layers of insulating board with an external lagging applied. These have neither the strength nor durability of double-wall metal construction.
If you have installed double-wall spiral duct, you already know how to install this product. Actually, its even easier to install than our fiberglass insulated products. The rigidity of the phenolic board and the close tolerances of our annular construction eliminate the need for an inner coupling. Most installations will only need external bolted companion angle rings or our economical SPOT-Flanges.
We can provide the inner and outer metal shells as galvanized steel (standard), paint-grip galvanized steel, epoxy powder-coated steel, PVC-coated steel, black iron, aluminized type 1 steel, 3003-H13 aluminum, 304 stainless steel or 316 stainless steel. We can provide the metal shells as spiral duct or longitudinal seam welded duct, and in thicknesses from 10 gauge through 26 gauge. We offer spiral lockseam construction, tack-welded and sealed construction, MIG and TIG welding. We can even offer the product as flat oval or rectangular construction. We can factory-assemble manifolds of duct and fittings to minimize field work. Essentially, we can offer just about all products from our SPOT catalog in PhenoliDuct construction.
This is the good part. We are a lot less expensive than the other closed-cell insulated duct products elastomeric, foam-filled and even other phenolic products. We arent spending time and money trying to overcome properties that dont lend themselves to the application. We simply developed a way to use the best rooftop metal duct fabrication SPOTs double-wall round spiral duct with the best rooftop insulation material Kingspans KoolDuct phenolic system. The result is 50% more R-value at 20-50% less cost.
Most engineers and contractors that work with educational facilities are familiar with standard HVAC design practices and SMACNA duct construction standards. But there are many specialty duct systems that fall under lesser known standards and criteria. The ducts used in vocational woodshop dust collection systems may outwardly appear to be the same spiral lockseam duct and fittings used for HVAC applications. The static pressure ranges may fall within those found in the SMACNA HVAC Duct Construction Standards. However, the actual requirements for a duct system in this application are higher and involve other standards. This Duct Construction Guide combines those various requirements into a single reference. This guide is not intended to cover commercial and industrial woodworking facilities. It lists the references used here, and most have greatly expanded ranges of size and capacity that can be used for those applications. The scope of this guide is as follows:
Dust collection ductwork may be fabricated to a more robust standard than typical HVAC duct, but the cost does not have to be egregiously higher. The products and methods we recommend are chosen to meet the requirements in the most cost-effective way. Dust collection ducts are recommended to be round in shape. Rectangular and flat oval ducts would require heavier metal gauges and extensive reinforcement. They also have less-efficient airflows and corners where particulate can be trapped. Traditional round blowpipe systems could be used, utilizing longitudinal seam construction. But a system using spiral lockseam construction will typically use lighter-thickness materials, with diameter/thickness ratios of as much as 1800. Greater stiffness is inherent in their construction.
Most vocational woodworking shop dust collectors operate in the range of -6 to -15 WG. For the relatively small diameters, the gauges are sufficient to avoid collapse. The particulate transported sawdust and small wood chips does not cause much impact damage or abrasion. Frankly, one of our greatest concerns we try to prevent is unintentional damage caused by the users. More than once, weve been consulted on jobs where HVAC-grade duct was installed and subsequently damaged. It seems a popular method for breaking up debris clogs is to whack the duct with a big stick instead of utilizing the cleanouts or disassembling duct for cleaning. The fittings and flange attachments need to be fully-welded construction. Most HVAC-grade fittings and assemblies use tack-welds, screws or rivets that are then sealed with mastics. Mastics should not be used on the interior of sawdust collection systems. Wood chips and sawdust would become embedded in the mastic, causing a chronic clogging issue. For all of the above reasons, the minimum gauge used for a vocational woodworking shop dust collection system duct is 22 gauge. In addition to durability, that is also the lightest gauge that can be consistently welded in most production facilities.
Dust collection systems are typically designed using the Constant Velocity method. Each item of shop equipment has a recommended flow rate of exhaust air either provided by the manufacturer or taken from a reference such as the ACGIH Industrial Ventilation (see Table x). Woodworking equipment generally pro-duces two types of debris. Sanders and band saws produce fine sawdust. Table saws, lathes, joiners and planers produce larger chips. Both types of debris have a Minimum Transport Velocity. That is the velocity that must be maintained from the shop equipment to the collector to avoid debris settling in the duct and potentially producing clogs. As ducts from different shop equipment merge into the trunk, the highest of the Minimum Transport Velocities must be maintained from that point to the collector.
Woodworking shop dust collection systems are designed for all equipment hookups to be drawing their recommended exhaust flow rates at any time the system is operating. Even though a saw or sander may not be in use, shutting off the exhaust flow from it would cause a decrease in trunk flow between that equipment branch and the collector. Those sections would drop below the Minimum Transport Velocity and clogs would potentially form. All of this makes sizing the ducts fairly easy. You know your cumulative exhaust flow rate (cubic feet per minute). You divide that by the prevailing Minimum Transport Velocity (feet per minute). The result is Square Feet of duct diameter. Simply round that down to the next available duct size. Table 3 below shows the available sizes of spiral lockseam duct from Spiral Pipe of Texas and their area.
Energy efficiency is as important in dust collection as it is in any other type of ventilation. But the need for Minimum Transport Velocities prevents design methods such as static regain from being used to reduce system pressure drop. Duct system layout, exhaust flow rate and the cumulative duct and fitting pressure losses dictate the system pressure and the required fan horsepower. Creating an energy efficient system really comes down to designing the most efficient duct system layout have the shortest possible distance between the shop equipment and the collector, and get there on the straightest line. It also helps to use efficient fittings, and we will go over them below.
Elbows and bends should be a minimum of two gauges heavier than the straight ducts of the same size used in a system. Elbow centerline radii should be a minimum of 2.0 with 2.5 recommended. All 90-degree elbows to 6 diameter should be 5-piece, larger sizes to be 7-piece construction. Angles other than 90-degrees should have a proportional number of segments. However, prefabricated elbows of smooth construction can be used. Where possible, we recommend the use of these die-formed elbows with a centerline radius of 1.5. The loss coefficients for these elbows is actually less than for segmented elbows with radii of 2.0 and 2.5, so you get better efficiency at a lesser cost. They are only available, however, in the smaller diameters. It should be noted that not all die-stamped or pressed elbows meet the minimum gauge requirements. Some are as light as 25 gauge. At Spiral Pipe of Texas, we only use 20 gauge die-formed elbows for this type of system, and only where the system design pressure allows 20 gauge construction in that size.
Woodshop dust collection systems use tapered body branch fittings. Most HVAC duct systems use barrel type fittings where the branch enters a constant-sized trunk. Any upstream reductions are made by putting a reducer on the upstream end. The problem with this type of fitting is that Minimum Transport Velocity is not maintained. Debris will settle out where both the tap and reducer meet the barrel, potentially causing clogs. Tapered body transitions are required, and a maximum 30-degree branch angle is preferred. The length of the tapered body should be a minimum of 5 times the difference of the upstream and downstream diameters. You should not try to effectively turn these branch fittings into 90-degree branches by combining the 30-degree lateral tap with a 60-degree elbow. That adds unnecessary field joints, additional pressure drop, plus an expensive elbow (60-degree elbows are not commonly available in die-stamped construction). The branch fittings in the trunk duct should be located on the collector side from the woodshop equipment, on a straight line from the elbow turning vertically down to the equipment.
Branch fittings entering the trunk directly opposite each other (crosses) should not be used. They create turbulence within the duct, leading to higher pressure drops and unpredictable transport velocity performance. If two items of shop equipment are located close to each other on opposite sides of the dust collector main, you should try to position them where their corresponding branch inlets, if extended across the profile of the main, do not overlap. The more separation, the better.
Most woodshop dust collection systems have manual blast gates at each piece of shop equipment. Simple aluminum cast-body gates are not expensive and have a thumb-screw for locking them in place. They should be located in the vertical duct riser from the shop equipment, approximately 42 above the floor for ease of access, and five diameters away from elbows.
They are generally not used for balancing the system or shutting off unused equipment. They are most commonly used in conjunction with floor sweeps and shop cleanup. The exhaust flow rates of the floor sweeps are not usually included in the total system volume. This is a cost-saving measure. A smaller system design flow means smaller duct and a smaller fan. When sweeping up the shop floor, you close the blast gates on the shop equipment, open the blast gates to your floor sweeps, then turn your dust collector on. You should do a separate system calculation to determine that your fan, with only floor sweeps open, can maintain the Minimum Transport Velocity for the cumulative floor sweeps of 4,000 FPM to avoid potential clogs.
Flexible ducts are commonly used for final connection to shop equipment. This allows some movement and positioning of normally fixed equipment. Such flexible duct should be as short as possible (2 foot maximum length recommended) and have a minimum amount of bending. The flexible duct should be a non-collapsible hose, rated for the pressure and for the intended use. Some equipment has a recommendation for a small-diameter flexible hose of longer length to be used where the attached pickup point is not fixed (blade guards on table saws and traveling heads on radial arm saws). Length should be limited to the expected movement.
A lot of money and limitations get added to shop dust collectors through the overuse of proprietary duct assembly systems. The idea of a system you can put together with external V-clamps sounds great, and you certainly avoid putting obstructions into the airstream like you would with traditional screw-and-glue HVAC duct joints. But to get those nice rolled duct ends, you have to go to longitudinal seam duct, and that limits your maximum lengths (shorter duct equals more joints to put together) and you end up with a lot of custom lengths or expandable lengths. We recommend a more practical and less expensive system of duct connectors.
The main trunks of dust collection systems are relatively straight runs in predictable and fixed positions. Most of the cutting and adjusting happens in the smaller runouts to the shop equipment. Our recommendation is to fabricate the main trunk lines of 14 diameter and larger as cut-to-length spiral lockseam pipe and fittings with flanged ends. Light gauge angle rings, such as the SPOT Flange, are sufficient for these applications and can be welded to spiral lockseam pipe ends and van-stoned to fitting ends. These flanges can be connected with self-tapping sheet metal screws be-cause such screws will not penetrate the airstream. If a joint is designed for disassembly, pre-punched angle rings can be used, and the flanges bolted together.
For ducts 12 diameter and smaller, we recommend us-ing the MU Overcollars from METU-System. These are a wide gasketed clamp with a single tightening bolt. They are very economical and make joint assembly fast. Best of all, you dont have to pre-order all of your small diameter ducts cut-to-length. This is very important when you are try-ing to make hard connections from your dust collector to shop equipment you may not even have yet.
Some material handling duct systems require seams and joints to lap in direction of airflow. This is intended to reduce particulate buildup when transporting long fibers that could snag on exposed metal ends. They are not required or recommended by any of the references used in this guide for vocational woodshop dust collection systems. Proper spiral duct systems follow tolerance standards that minimize the gap between male-sized fitting and coupling ends and the female-sized ends of spiral duct. The goal is a friction fit. You should have a little bit of metal scraping when you insert a slip fitting into a section of spiral duct.
Cleanouts should be used in horizontal duct runs, near elbows, junctions and vertical runs. They should be spaced a maximum 12 feet apart for ducts 12 diameter and smaller, and maximum 20 feet apart for larger diameters. For small diameter branches to equipment, the removal of a duct section with the use of the MU Overcollars is an effective cleanout. For the larger primary trunk ducts, removing a section for cleanout is less desirable and practical. The most cost-effective method for producing a good cleanout is through the use of removable caps. We have already mentioned a removable cap for the last branch of the trunk ducts. Within straight sections of trunk ducts, lateral branches with removable caps can be added. For 90-degree directional changes in the trunks, removable caps can be utilized by having either heel-tapped elbows or using a lateral branch + elbow for the primary flow (for 12 and smaller). Recommended cap size is trunk diameter 2 for branches from the main, up to a maximum 12 diameter cap size. Caps on the through-end of branch fittings should be the same diameter as the trunk duct. The removable caps are fixed in place with an MU Overcollar, so they can be easily removed with a single bolt.
The recommended maximum leakage for a dust collection system is 2%. As with any duct system, a substantial portion of the leakage occurs at the duct joints. In woodshop collection systems, the additional sources of leakage are the slide blast gates and cleanouts. The use of the gasketed MU Overcollars will eliminate most leakage at joints and cleanouts. Other types of cleanouts such as split sleeves and hinged access doors have been commonly used, but once opened, they are notoriously difficult to keep sealed. Rectangular connections and openings should be avoided because of their tendency for corner leakage.
For suspension and support, the weight of dust collection duct is calculated as the weight of the duct itself, plus the weight of the sawdust filling half the duct. Table 4 has nominal design weights for Vocational Woodworking Shop Dust Collection Systems using spiral lockseam duct. Ducts can be suspended using appropriatelysized cable hangers, teardrop strap hangers or saddles. Hangers should be located as close as possible to joints and elbows (2 recommended) and maxi-mum 12 feet apart. Longer hanger spacing can be used if the duct joints are flanged and guidelines found in the SMACNA Round Industrial Duct Construction Standards are followed (sections 4.10 and 5.8). Duct systems covered in this guide are not intended to be walked on, so the 250 pound maintenance load can be omitted.Get in Touch with Mechanic