2020年8月1日星期六

[FS] 問﹕Smoke Head False Alarm 有啲乜方法解決？

答﹕

首先檢查係乜原因 false alarm, 唔同成因唔同對策


响安裝方面，可以加條 U-Shape flexible conduit 而唔用硬管，避免有水直接入落個smoke head度；又或用防水底座；


潮濕引致的話，有啲Smoke head 係特別能夠抗潮濕環境，到到R.H. 95%以上；


有塵的話就清潔或換頭；


有煙的地方如煮食，就用multi sensor;



(鳴謝﹕肥喵、肥M)
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2020年7月23日星期四

[EL] 問﹕Motor Starting 有邊幾種方法？

答﹕

首先講點解要有Starting.
起摩打嗰陣，個back EMF 未建立，起動電流會好大，電流過大首先會過熱燒斷電線，仲有會忽然chur太多電令其他電器電流忽然少咗，輕則電燈會閃下，重則電腦都同你熄埋。

常見Motor Starting 方法有

1. Direct on line, 簡單嚟講即係乜都冇，直接點著個摩打。

2. Star - Delta
Star 接法 line current 細好多
但Delta接法 Line Current 就大一大截
所以有個做法，就係先起動個Main Contactor + Star Contactor起咗機先, 行一陣再用個timer 轉接過Delta Contactor, 咁就可以降低個Coil current. 不過同時起動個力同速度都會有所減弱

3. Autotransformer
逐級升Voltage嚟減少一開始既電流

4. Soft Starter
裡面主要有舊叫Triac既嘢嚟降低初始電壓
同DOL比較，要去到最終速度同電壓既時間都會耐咗


5. VFD
原理大概係先由一組Diode將AC轉做DC，再由Capacitor整波Filter, 最後由一組Transistor出返AC. 可由RS485控制


Soft Starter 同 VFD 除咗原理唔同外，最大分別係前者平啲細舊啲，但冇得通過控制Frequency嚟控制速度

計數方面﹕

Direct on line - x 7

Star Delta - x 2.5

Autotransformer - x 2-3

VFD - x 2-3



(Source: The Engineering Mindset; Realpars)
於 1 則留言:

2020年7月12日星期日

[AC][EL][FS][PD] 問﹕各類型空間响BS Engineering Design上係要注意？

答﹕

Artium 中庭﹕Smoke Extraction, glass panel, OTTV Limit + natural lighting / tubular daylighting, ELV - audio / video / speakers, projection screens for performances or special events


Auditorium 劇院﹕Drencher System, beam detector + long throw sprinkler + Flame detector, smoke extraction, displacement ventilation (duct works underfloor, modulating volume control damper, plenum 1.5m/s, supply diffuser 0.15m/s), NC level 20-30, orchestra pit, stage lighting
Child Care 幼兒﹕IAQ, Natural lighting

Court Room: NC level 25-30, UPS, 1000 lux

 Hotel: License from Home Affairs Department

Lobby: Air curtain

Mail Center: HEPA filter (HK有必要？)

Car Park: EV Charger, CO sensor, hydraulic lift, petrol interceptor


Physical Fitness: latent load, negative pressure

Plaza: Waterproof socket

Dangerous Goods: 

  • Fixed Sprayer, Portable / Automatic Fire Extinguisher, Heat detector, Flammable gas detectors, 

  • 5ACH, Elector-thermal link fire damper;

  • Flameproof Fluoresent Luminaire, mineral insulated cables, explosion proof socket (唔係防爆炸，係防火花), 

  • Ultrasonic level transmitter, flameproof emergency manual override to stop fuel pumping system, overflow / sensor, emergency oil cut


Underground Space: sump pump

Mortuary: Pathogens through Airborne particles from cadavers, 20ACH;
Natural lighting, sufficient for working and psycological 

Columbarium: 
License by FEHD, including 
FSD Vent/425, FSI 314, FS 251, FS 163 Dangerous goods, min. distance from 化寶爐;
EPD 化寶爐 smoke exhuast location and treatment; 
一啲偏遠冇污水渠既地方會用呢個方案，先經化糞池，再經滲水池將啲污水drain落泥度，化糞池裡面啲嘢就由泵車泵走。

Nosie Control

於 1 則留言:

2020年7月2日星期四

[AC] 問﹕Fume Cupboard Design 有啲乜要留意？

A.      Function of fume cupboard

-    To  remove  fumes  effectively  so  as  to  keep  the concentration of the contaminants  in the breathing zone of the operator to below the exposure  limits  and  also  to  prevent  the  build up of an explosive atmosphere inside the FC.

-    To place a physical barrier between users in the laboratory and the work inside the fume cupboard.

-    To provide an effective containment device and exhaust in case of accidental spills and emergency.


B.      Type of fume cupboard

-   Conventional fume cupboard

-    CAV (Constant air volume- when sash is lowered down, high face velocity ie Q=VA, turbulence occur, bypass with modulating valve should be added

-    VAV air volume, the exhaust air is controlled to maintain face velocity in preset value when the ash is partially closed.

-    Auxiliary air fume cupboards- same as conventional fume but add dedicated makeup, reduce energy loss of return air taken by fume cupboard. Exhaust venturi valve interlock with make up air to maintain negative pressure for the fume cupboard.

-    Re-circulatory or ductless fume cupboard- no direct exhaust to open air, independent exhaust and re-circulate by filter

-   Water supply point with drain

C.      Design checkpoint

-    Location: away from normal traffic pattern, cross-draughts, air inlets and other sources of disturbance, exit from a work space (may have potential risk of fire or explosion in fume cupboard)

-    Face velocity = 0.5m/s

(鳴謝﹕紅豆)

於 沒有留言:

[AC] 問﹕Chiller 運作原理係點？有啲乜保護方法？

答﹕

理解咗個運作原理，要保護啲乜就容易理解得多，個chiller由四個主要部件組成，Compressor, Condensor, Expansion Valve, Evaporator; 當然，個compressor仲要有motor推動，同埋個system裡面要有refrigerant

又或者Youtube睇一轉

個Chiller最頂嗰舊係Compressor, 低一倉係Evaporator, 最低嗰倉係Condensr

Condenser: 
High / Low Return Condenser water temperature / Reduction of water flow in condenser (Water Cooled) / Reduction of air flow in condenser (Air Cooled) / High / Low Ambient Air Temperature (Air Cooled)
If no flow signal, the pump will automatically interlocked for changeover to the standby pump.

Evaporator:
Evaporator Low Cut / Low flow 

Expansion Valve:
Blocked expansion valve

Compressor:
Oil: Lubrication Oil Level / Oil Pressure
Electrical: Motor, VSD, Panel High Cut / Over Current / Votage High, Low / 3 phase unbalance / Surge Protection

Refrigerant:
Purge for non condensable in refrigerant loop / System Pressure 


(鳴謝﹕紅豆、K、諾克Sir; Source: https://youtu.be/Zu0LVVNNVSw ; https://www.youtube.com/watch?v=K0xAKzdROEg)

於 沒有留言:

[EL] 問﹕球場 Football Field / Stadium Lighting Design 有啲乜要注意？

答﹕

FIFA (國際足盟大賽)，UEFA(歐洲冠軍聯賽) 標準

Class I (Amateur 業餘) 
- 200 lux, 0.5 uniformity

Class II (Semi Professional)
- 500 lux, 0.6 uniformity

Class III (Professional Stadium)
- 750 lux, 0.7 uniformity

不過上述都唔足以做TV broadcasting, 大概要滿足以下條件先做到
- 1000-1500 lux, uiformity U1 0.6, U2 0.8, Colour Rendering Index 70 以上(0-100Ra)
- Floodlight Luminaire Mounting: 
原則﹕唔好比影擋到，大概25-30m

兩側﹕光到達球場中心嗰點要响25°同45°之間
Goal line: 
45°同60°之間


於 沒有留言:

2020年5月25日星期一

[BIM] 問﹕如果只有一個Navisworks nwd檔，點樣攞啲pipe size / pipe length 出嚟?

答﹕

步驟一﹕按Quantification-->Project Setup, 跟住comment sense 按next, finish

步驟二﹕按一下你想take數既pipe, 按properties, 睇下個pipe diameter 係响邊個catagories 下面，之後記住佢，以呢個例子，係用"DWF - Mechanical"呢個標簽下既數字。
要注意既係，可能有好幾個catagories下面都有pipe diameter, 如果係咁的話一定要搵個係後面冇

Ø

符號既，如果唔係就會take 唔到數。

呢種value就會take唔到

步驟三﹕响Quantification Workbook一欄度滑鼠右鍵，按"New Virtual Takeoff", 之後新增一堆你想take數既item, 今次以dia 150mm 及  dia 100mm 消防喉嚟做例子。

步驟四﹕選擇你想take數既pipe, 用Find Items再揀Properties嚟篩選

步驟五﹕用以上篩選器選擇後，按"Find All", 個模型所有响"Welded Steel Pipe" 下既dia 100mm pipe 都會著藍色被選，之後直接將堆已選既pipe拉入去新開個item入面，如下圖

步驟六﹕每條dia 100mm 既pipe 長度，總長度等，都可以出晒嚟。亦可以export 出excel or XML. 大家有冇留意，Navisworks比到出嚟既屬性係冇Pipe Diameter呢項，以上都係半手動式咁篩選，如果想响個表直接出齊Pipe Diameter + Pipe Length, 有另一個方法

---------------------------------------------------------------------------------------------------

同以上步驟一樣，但選擇晒所有你想take數既pipe

之後按"Item Catalog" --> "Property Mapping" --> 揀選有效既Pipe Diameter (上面有講)。呢個步驟目的係，既然ModelPerimeter裡面冇嘢，就攞個有用既diameter霸咗佢呢項。

跟住選晒所有item, 响堆item度右鍵"Delete Takeoff", 再重新將堆pipe拉入嚟run一次，就可以Pipe Length + Pipe Diameter 同時响個表度出面
於 2 則留言:

2020年5月21日星期四

[BIM] 問﹕DevB 發展局嗰廿項BIM Use 分別係乜嚟？

答﹕


1. Design Authoring
開一單BIM Project最基本既嘢，Information related e.g. Data Base, Quantities, Schedules; Graphic Related e.g. 3D view, plan, elevation, section;
做上述嘢响香港比較常用既軟件有Revit, ArchiCAD (Architural); Tekla(Structural)

2. Design Reviews
即係睇個BIM模型，通道/照明等。
Modelling software, or Navisworks; BIMx; Enscape or Fuzor (Real Time Rendering) 或好多CDE平台都做到

3. Existing Conditions Modelling
最常見都係用3D Laser scanning 將成個現場掃入做point cloud, 用嚟做design planning; 亦可以係as built 後再掃對返個BIM model. 
一般有兩種方法，第一種係topography, 攞般拍機嚟影堆相，再跟據標誌物高度同相機focal length比較返嚟估個coordination, 真係得個睇字幾唔準，但好處係快，幾大個Site一朝可以搞掂；另一種係攞部百幾萬既Laser scanner 射無數束laser出去再反射返入嚟計個位置，相對準好多，不過功夫同成本都高得多，要不斷移部機位置將N個point cloud 砌返一齊。兩者都可以砌返啲360°相入個point cloud度。 
Leica, Faro 都有出呢啲3D laser scanner

4. Site Analysis
即係Geographic Information System, 可以用嚟分析日照、陰影、視野、水浸風險、屏風樓、UU嗰類。
Esri ArcGIS, Spatial Technology

5. 3D Coordination
即係睇有冇碰撞，BIM最基本既功能。香港主流做法都係Revit model完再放入Navisworks出個clash detection report

6. Cost Estimation 
即係5D, Design Stage個Model做完可以用嚟出到個quantities; Consturction Stage 可以用嚟計VO, Interim Payment etc.
香港會用到既軟件有Vico Office, QIM5D, CostX, YTWO 5D BIM, MTWO

7. Engineering Analysis
Revit 都自帶Structural Analysis;
MEP方面，Revit 自帶計Cooling Load. 當然仲有好多種玩法如export個BIM去做CFD
軟件有Autodesk CFD; Export to DIAlux for lighting simulation; Acoustic有人用MS Visual Studio做;

8. Facility Energy Analysis
做好個BIM model 後，用Autodesk Forge將啲MEP equipment sensor同個BIM link 起嚟，咁就可以直接用個BIM嚟訊號或落指令，收到數據後再進行分析。

9. Sustainability Evaluation
香港既代表係"Hong Kong Beam Plus Assessment Tools Eco Designer Stars", 將成個BIM model 放入軟件去做BEAM Plus評分

10. Space Programming
Architectural 而言，可以自動生成N種building唔同形狀方案，用Revit 個 Dynamo可做到

11. Phase Planning 4D
唔洗多都明，做成個construction sequence simulation, 開工後成個地盤佈局，天稱，物料存放，車路行人路等等，都可以用BIM嚟show
常用既有Navisworks, Fuzor, VicoOffice

12. Digital Fabrication
將啲DfMA, MiC element响BIM出埋construction details去生產；再進一步可以出埋啲放得入Computer Numerical Control Manchines (數控機床，類似3D Printer)既格式直接生產組件。

13. Site Utilization Planning
同4D類似，响construction stage 做空間、物流、temp works, safety規劃

14. 3D Control and Planning
簡單嚟講就係用GPS嚟管理project elements e.g. Wall survey points, 比起傳統墨斗佬開墨方便得多。

15. As-Built Modelling
泥水圖有既嘢諸如房名、樓梯名；或door, window, louver schedules; 或MEP嘢，全部要齊，同以往交As-Built Drawing一樣

16. Project System Analysis
一開始做Design會用BIM做CFD之類analysis, 棟樓起好後再比對返同之前simulation result吻合否; 又或用個BIM嚟比對現場同個BIM分別。EcoDumus可做到。

17. Maintenance Scheduling
將傳統maintenance schedule同個BIM結合

18. Space Management and Tracking
攞個BIM嚟做空間管理，諸如平時返工Book會議室，再可進一步直接由個BIM度睇到間房有冇人用緊

19. Asset Management
可用Autodesk Forge做IOT，直接响BIM度操控啲control panel如燈，冷氣

20. Drawing Generation
BD 相關嗰啲圖如GBP, Superstructure Plan, Excavation and Lateral Support ELS, Foundation Plan Drainage Plan etc. 已經出晒Guideline教大家點出圖；
MEP圖上比EMSD/ WSD/ FSD 等政府部門既出圖標準都好快問世；CSD/CBWD等市場已經做咗好多年。最大爭議都只係上下打疊既pipe/duct用啲乜方法嚟present
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2020年5月10日星期日

[FS] [PD] [EL] [AC] 問﹕最終啦BD攞OP要集齊啲乜？

[FSD]


[WSD]

WSD 消防水及清水supply cert., see https://elvissharing.blogspot.com/2020/03/pd-project.html

[DSD]


[EMSD]

Lift Use Permit; Disable Lift Cert., (唔一定有呢樣嘢) see https://elvissharing.blogspot.com/2020/03/el-lift-elevator.html

[BD]

Fire Resistance Materials, Frameworks, U/G Drain test report https://elvissharing.blogspot.com/2020/05/ac-pd-renewinno-bssubmitbd.html


OP之後仲會有機會有張由Lands Department 地政總署批出既Certificate of Compliance, 證明呢幅地既用途係滿足批地條件。
於 1 則留言:

[FS] [AC] 問﹕入FSD Statutory Submission 包括啲乜？

答﹕

有三條Routes要做，1. 批GBP; 2. 批FS System (再分兩部份，包括 i. FS System e.g. FH/HR/Sprinkler; ii. Mechanical Ventilation related including Smoke Extraction, Staircase Pressurization, VAC); 3. 批Dangerous Goods;

Routes 1: GBP 比FSD 批則 (BD會搞掂埋)。 最後夾埋FS 314, FS 501 一齊上；

Routes 2: 批成個FS System
响design stag(Stage 1) 先交個schematic (FS 同 MVAC分開交) 上去，呢個時候唔洗交平面圖住，滿意後FSD會出張 FS 161.
到Detailed FSI Layout Drawings Submission (Stage 2) 先連埋平面圖一齊夾埋FS 314, 501一齊上。

Routes 3: 
Dangerous Goods. 先上比FSD批圖；如果有Mechanical Ventilation 就要上埋 FSD (Vent / 425-DG) for comment. (酒店都有Vent / Hotel-02A) 批完裝好後搵FSD嚟驗。驗好後業主交License Fee, FSD issue DG License;

Fire Service Installation and Equipment 要有埋張FS251 Certification;

以上齊晒後FSD就會响十四日內過嚟驗消防，合格後會收張FS 172, 最後驗樓OP就靠呢張嘢。

於 2 則留言:

[EL] 問﹕一棟新樓由向電力公司攞電到打到電個流程係點？

答﹕

首先係要由顧問交圖等比CLP中電或HEC港燈，批咗後就申請駁電。

當然，駁電係由兩間電力公司做冇可能Develper or Main Contractor做，所以係要啦業主收錢。

呢個時候兩電就會出張繳款通知書Demand Note 叫業主交錢。

之後就Main Con + Sub Con. 努力揼起個火牛房，揼起之後搵兩電嚟驗收。

收咗牛房後，牛房內既嘢係兩電自己做返；崛路駁大電纜都會有兩電做；
電氣Sub Con呢個時候亦會好努力繼續做埋其他嘢，包括所有Cabling works, earthing, 簽WR1; 兩電都會檢查啲嘢做成點。

搞掂晒之後就可以啦兩電申請掛電錶，跟住兩電會嚟裝電錶。

最後就有永久電用。

於 1 則留言:

[AC] [PD] [Renew./Inno.] 問﹕除咗渠之外，BS仲有啲乜嘢係要submit比BD？

答﹕

入BA13嗰陣除咗堆UG Drain Test Report 外 (見 http://elvissharing.blogspot.com/2020/05/pd-bsstatutory-submission-drainage.html) 仲有兩樣嘢要預備﹕

一樣係PNAP APP-13既Fire Resistance Materials, BS嘢包括Fire Damper, Fire Shutter, Lift Landing Door, Cast Iron Pipe; 

另一樣係Framework相關 (唔係用minor works嚟入)，舉例有Fiberglass Tank, Solar Panel, Cooling Tower, External AC Hanger etc.;

Fiberglass Tank 深過2m 或大過9

m³

就要入；其他則冇指定。

個過程都幾麻煩，先要預備好晒呢啲Framework Drawing and Calculation, 之後比RSE簽，跟住比BD Approval先開工，再之後預備一堆Welding/Anchor/Mill Cert等文件响BA13嗰陣入埋。

仲有樣嘢係BS關BD事，係OTTV submission related, see http://elvissharing.blogspot.com/2020/04/ac-cooling-load.html

於 沒有留言:

[AC] 問﹕新冠肺炎下BS系統設計有啲乜地方要注意？

答﹕

[AC]

- 加大ACH及Exhaust; 
- 有疑似病例出現的話，可用類似VAC cut 咁局部停冷氣；
- Thermal Wheel 嗰種heat recovery 要停用或改做，加條by-pass air duct比佢；但Plate Type嗰種就可以照常用；

- Return關盡，Exhaust開到最大；
- 有reheat就開，不過香港都冇乜機會有；

[PD]
- 確保足夠水响U Trap, 好廢既標準答案;
- Design of Stack high / low zone, 適當Size條Vent Pipe, 減少條S.W.P.堵塞，防止Hydraulic Jump
- 避免用呢啲Hopper因為係open system
- 加Set UV 响樓上嘅vent pipe度，如圖

- 啲水封高度，pipe size乎合BD要求

(鳴謝﹕紅豆，K；Source: 辨公建築應對新型冠狀病毒指南)
於 4 則留言:

2020年5月9日星期六

[PD] 問﹕做BS有啲乜Statutory Submission 係同Drainage有關？

答﹕

DSD + BD

Building 尾井至政府井嗰段係要同DSD交手。

做呢段渠有兩種做法

第一種係入DSD form 25 等DSD駁，DSD駁完啦業主攞返錢，但一般都唔會咁做，個崛路期唔容易控制。响地盤度門口出入位係相當關鍵，如果夾唔啱個期你有你做，DSD有DSD做，玩完。
第二種係Main Contractor 攞住張BD批則後自己駁 (界內既渠係BD睇，包括界內地渠；但界外尾井至政府井呢段就係DSD睇，入則比BD時，BD係會自動波幫你遞埋比DSD comment)

攞到Excavation Permit 後，Main Con 自己夾個期幾時駁，差唔多同步入一張叫HBP1既form同交錢，約DSD嚟驗收呢段。駁筒或做新井既時候記得要photo record. 最後要將啲material list, drawings (燒碟，mircostation format), CCTV (拍得唔靚仔記得要拍過)等交比DSD。

搞掂晒後DSD就會出封信比你話可以用嚟discharge.

界內所有渠都要同BD交手。

大樓渠都冇乜特別，最緊要都係跟足BD批圖，尤其係個pipe duct 嗰啲順時針順序排列。
有sunken 要 Fill 輕石矢地方最好就做晒photo record and drain test, 雖然例冇講，但個個BD人收法都唔同，有啲又話要有啲又話唔洗。

但地渠嗰啲form就一定要，即係PNRC 11叫BD落嚟睇驗渠 (咁多年嚟我一次都未見過佢地會真係落嚟) ，再由AP簽張PNAP 157確認。呢啲就真係要做足photo record, 最尾申請驗樓BA13前要成疊完完整整交上BD。

驗既方法好簡單，就係塞住條渠一頭，另一頭棟條膠筒再注滿水浮舊發泡膠，過一排唔drop就即係接位冇漏/條渠冇裂。
要留意BD好多人唔識嘢，响BS8301度好清楚寫住係可以咁用條膠管駁住試地渠
即係咁

但佢地唔肯收，一定要見到成條膠筒直駁住

冇計，就算擺明係佢地打橫嚟都唔好拗，鬼叫你要驗樓
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